Method for obtaining commercial feed juices having a more hand-squeezed character

ABSTRACT

A method for obtaining commercial feed juices having textural, aroma and flavor properties more like hand-squeezed orange juice is disclosed. This method involves gentle extraction of orange fruit with commercial juice extractors, gentle and quick removal of rag, seeds and peel from the extracted juice, substantially complete removal of sensible pulp, and removal of at least some of the sinking pulp. The feed juices obtained have a relatively low viscosity and sinking pulp level, minimized levels of peel oil and flavanoid glycosides and a relatively high ratio of more desirable orange compounds to less desirable orange compounds.

TECHNICAL FIELD

This application relates to commercially processed orange juice productswhich are closer to hand-squeezed orange juice in character than currentcommercial products. This application particularly relates to a methodfor obtaining commercial feed juices useful in preparing such products.

For many people, the "gold standard" of orange juice beverages isfreshly hand-squeezed orange juice. Hand-squeezed orange juice has manyproperties which are desirable to the consumer. These properties includethe color and hue of the juice, its foaming characteristics, and theappearance of floating, intact juice sacs. In addition, hand-squeezedorange juice has a particularly pleasing, fruity aroma and flavorcharacter.

Hand-squeezed orange juice also has unique textural characteristics.Somewhat surprisingly, hand-squeezed juice exhibits pseudoplasticbehavior, i.e. is "shear-thinning." This pseudoplastic behavior isespecially apparent at shears associated with sipping and swallowing oforange juice. For example, hand-squeezed juice from Florida Valenciaoranges has a relatively low average viscosity of from 4 to 6 centipoise(measured at 8° C.) at shear rates of 10 to 100 sec⁻¹ which approximatethe shear of sipping and swallowing.

This unique drinking texture of orange juice is believed to becontrolled by at least two different factors. One is the amount ofbackground or "sinking" pulp present in hand-squeezed juice. Thissinking pulp, while fairly small in size (i.e., passes through a 20 meshscreen), influences significantly the viscosity of orange juice. Theother is the relatively low levels of pectin and hesperidin, the majorflavanoid glycoside present in the pulp, peel and rag. The cloud inorange juice contains an assemblage of needle-like hesperidin crystalsstuck together with pectin. It is believed that this assemblage ofhesperidin and pectin influences, to a lesser extent than sinking pulp,the viscosity of orange juice.

The unique properties and characteristics of hand-squeezed orange juiceresult, in large part, from how it is made. Hand-squeezing involvesfairly gentle extraction of juice from the orange fruit. This gentleextraction minimizes the introduction of off-flavor compounds, as wellas materials which adversely affect color and texture. In particular,hand-squeezing prevents the introduction of significant levels of peeloil and other off-flavors which can impart a bitter flavor character tothe juice. Hand-squeezing also minimizes the grinding of juice sacs intoviscosity-increasing sinking pulp. There is also typically less abrasionof the rag and albedo portion of the peel which contain off-flavorcomponents, as well as hesperidin glycosides and soluble pectin.

Hand-squeezing oranges is not a practical way to generate commercialquantities of orange juice. The yield of juice from orange fruit byusing hand squeezers is fairly low, typically on the order of about80-90%. Even if commercial quantities of juice could be extracted byhand-squeezing, it would not be economical to distribute it in thatform. Hand-squeezed orange juice contains about 85 to about 90% water.The most economical way to store and distribute orange juice is inconcentrated form. Indeed, the bulk of orange juice commerciallyprocessed in the United States exists in concentrate form.

Another factor which would make distribution of hand-squeezed orangejuice impractical is its lack of storage stability. Hand-squeezed juicecontains pectinesterase enzymes which can demethoxylate pectins presentin the juice. These demethoxylated pectins can form undesirablejellified lumps over time which increase the viscosity of the juice. Inaddition, because hand-squeezed juice has a relatively high wateractivity, it is subject to microbial spoilage in a relatively short timeperiod unless pasteurized.

Commercially processed orange juice products have tried to approach thequality of hand-squeezed orange juice. These attempts have not beencompletely successful. The lack of hand-squeezed character incommercially processed juice products is due in large part to thequality of the starting feed juice. Current commercial feed juicescontain significant levels of undesirable components or contaminantswhich are very difficult, or impossible, to remove during subsequentjuice processing.

In commercial operations, the quality of the starting feed juice isdetermined by essentially two factors. One is the quality of the fruitwhich is used. The use of over-ripe, immature or very small fruit cancontribute undesirable flavor compounds and contaminants to the feedjuice. The other, more significant factor is the equipment used in juiceextraction and finishing, in particular the conditions under which thisequipment is operated. Operating conditions usually involve a compromisebetween quality of the juice and the yield of juice from the orangefruit. Generally, the higher the quality of the feed juice, the lowerwill be the yield, and vice versa. Accordingly, targeting a feed juiceto have the characteristics of hand-squeezed orange juice is not an easychoice, given the potential adverse economics of a low juice yield.

Even if the feed approaches hand-squeezed quality, further commercialprocessing can adversely affect its properties. The characteristic"fresh" compounds of freshly hand-squeezed orange juice include the lowmolecular weight alcohols (e.g., ethanol and methanol), aldehydes (e.g.,acetaldehyde) and esters (e.g., ethyl butyrate and ethyl3-hydroxyhexanoate). Since these compounds are relatively volatile, theycan be easily lost due to volatilization. In addition, these delicatecompounds, as well as other less volatile compounds such as valenceneare easily degraded during evaporative heat concentration processestypically used to remove the bulk of water from the feed juice.

One method for preserving these delicate aroma and flavor volatiles isto strip them from the feed juice before evaporative concentration. Onesuch process is disclosed in European patent application No. 110,638 toPowers et al, published June 13, 1984. In the Powers et al process, thefeed juice is stripped with steam or inert gas to remove orangearoma/flavor volatiles. These stripped volatiles are then condensed atprogressively colder temperatures preferably in the range of 95° to -50°F. The resulting aroma/flavor condensate is separated by centrifugationto provide an aqueous stripper essence and a stripper oil. The stripperessence and stripper oil are subsequently added back to the concentratedstripped juice.

The Powers et al process is basically preservation in nature. This meansthat whatever volatiles are stripped out of the feed juice will beessentially present in the stripper essence or stripper oil. Thisincludes off-flavor volatile components as well. Accordingly, thequality of the feed juice can determine greatly the quality of theresulting stripper essence and stripper oil obtained by the Powers et alprocess.

After the delicate aroma and flavor volatiles have been removed from thefeed juice, it is then concentrated. Most commercial concentrationprocesses utilize heat evaporation techniques to remove the bulk ofwater from the juice. In addition to removing water, these evaporativeprocesses also serve additional functions. One important function is todeactivate enzymes present in the juice, in particular pectinesterase.

The standard evaporative system for concentrating feed juice utilizestemperature accelerated short-time evaporators (TASTE). TASTEevaporators concentrate by heating a flowing film of the feed juice withsteam or vapor previously generated from the feed juice. In a standardseven-stage, four-effect TASTE evaporator system, the feed juice isheated at progressively higher temperatures, starting at 40° C., andpassing through a maximum evaporative temperature of 96° C., followed byheating at progressively lower temperatures ending at 40° C. where theconcentrated juice attains a solids level of 63° Brix. See Nagy et al,Citrus Science and Technology, Vol. 2 (1977), pp. 217-218.

TASTE evaporative systems can impart cooked off-flavors to the resultingconcentrated orange juice. This is due to a combination of relativelylong times (minutes) to which the juice is subjected to relatively hightemperatures, e.g. as high as 96° C. TASTE concentrates (58° to 72°Brix) derived from current commercial Florida feed juices can also haveviscosities of from about 8,000 to about 20,000 centipoise at 8° C. Evenwhen these TASTE concentrates are diluted to single strength, they haveviscosities much higher than that of hand-squeezed orange juice.

BACKGROUND ART

A. Selection of processable fruit

Nagy et al, Citrus Science and Technology, Vol. 2, (1977), pp. 183-189,contains a general description of how citrus fruit is prepared forprocessing. Nagy et al teaches that during sorting, badly damaged,softened, over-ripe or otherwise low quality or unwholesome fruit isremoved by hand during sorting of fruit. This reference also states that"fruit may be stored in bins for 12 to 72 hours before processing." Whenreferring to mechanically harvested fruit, Nagy et al say the fruitshould be handled as quickly as possible to minimize the time betweenharvesting and juicing.

Ranganna et al, "Citrus Fruits. Part II. Chemistry, Technology andQuality Review., B. Technology," CRC Critical Reviews in Food Scienceand Nutrition, Vol. 19 (1983), pp. 4-5, also gives a general descriptionof the handling and sorting of citrus fruit before processing. Rangannaet al state that unwholesome fruit must be removed before processing.This reference also states that, after washing, the fruit is inspectedagain to remove damaged fruit missed earlier or subsequently damaged.

B. Extraction and finishing of juice

Nagy et al, supra, at pp. 188-99, gives a general description of juiceextraction and finishing as it applies to the citrus industry. Nagy etal teach that the juice finisher and extractor are important to thenature, quality and characteristics of the citrus juice or concentrate,and can be adjusted to control the amount of pulp, oil, etc., in thejuice. This reference specifically refers to the Brown model 400 and 700juice extractors as producing a high quality juice that is very low inpeel oil content.

Ranganna et al, supra, at pp. 6-7, also provide a general description ofjuice extraction and finishing. Ranganna et al teaches that the settingand operation of the juice extractor and finisher determines the yieldof the juice and its quality characteristics. They state that the goalis to remove as much juice as possible from the fruit without grindingthe pulp or membrane or extracting oil and juice from the peel. Thisreference also indicates that he pressure exerted during extraction ofthe juice has a significant effect on its quality and that excessivepressures produce juice having higher contents of bitter limonin, totalpectin, serum viscosity, oxygenation of terpenes and aldehydes from theflavedo, septa, and seeds, etc. Conversely, juice extracted with lesspressure has higher color values and better flavor.

U.S. Pat. No. 4,518,621 to Alexander, issued May 21, 1985, discloses ajuice finisher for removing solids from extracted juice. In thisfinishing machine, extracted juice is introduced into a rotatingcylindrical screen. The centrifugal force generated urges the fluidportion of the juice outwardly through the screen while retaining thesolids. A plurality of paddles are arranged for rotation within thescreen to uniformly spread the juice along the inside surface thereof tofacilitate separation. This finisher is alleged to separate the fluidportion of the juice from the solids in "a relatively gentle manner" and"without harsh mechanical pressure being applied against" the juiceentering the finisher. The main benefit alleged is the prevention ofsolid components from being forced through the screen.

U.S. Pat. No. 3,385,711 to Sperti, issued May 28, 1968, discloses theproduction of orange juice and orange juice concentrates which remainpalatable throughout reasonable periods of storage under proper storageconditions. This patent states that the development of bitterness injuice products is due to pulp present in the juice. This bitternessproblem is prevented by separating the pulp from the extracted juice bycentrifuging, filtering or decanting and then adding pulp which does notdevelop undesired bitterness characteristics.

DISCLOSURE OF THE INVENTION

The present invention relates to a method for obtaining commercial feedjuices having textural, aroma and flavor properties more likehand-squeezed orange juice. This method comprises the steps of:

a. selecting processable orange fruit;

b. processing the selected fruit by:

(1) gently extracting the selected fruit in a commercial juice extractorto provide extracted juice having about 0.015% or less titratable peeloil;

(2) gently and quickly removing nonjuice materials from the extractedjuice to provide a partially finished juice;

(3) removing sensible pulp from the partially finished juice to providea completely finished juice substantially free of sensible pulp andhaving:

(a) a viscosity of at least about 10 centipoise at a temperature of 8°C.; and

(b) at least about 10% sinking pulp; and

(4) removing at least some of the sinking pulp from the completelyfinished juice to provide the commercial feed juice.

The commercial feed juices resulting from the method of the presentinvention, which are substantially free of sensible pulp, can beobtained from either Valencia orange fruit or non-Valencia orange fruit.The Valencia orange feed juices have:

(a) a viscosity of about 10 centipoise or less at a temperature of 8°C.;

(b) about 10% or less sinking pulp;

(c) about 0.015% or less titratable peel oil; and

(d) about 175 mg. or less, per 100 ml., of flavanoid glycosides.

The non-Valencia orange feed juices having:

(a) a viscosity of about 8 centipoise or less at a temperature of 8° C.;

(b) about 8% or less sinking pulp;

(c) about 0.015% or less titratable peel oil; and

(d) about 200 mg. or less, per 100 ml., of flavanoid glycosides.

BRIEF DESCRIPTION OF DRAWING

The FIGURE shows schematically a preferred evaporative concentrationsystem used with the present invention.

A. Obtaining Feed Juice from Orange Fruit

A key aspect of the present invention is the starting feed juicesobtained from orange fruit. The physical and chemical composition ofthese feed juices is unique, especially compared to current commercialfeed juices. However, the textural, aroma and flavor properties of theseunique feed juices are such that they are more like hand-squeezed orangejuice. Surprisingly, preferred feed juices of the present invention(titratable peel oil content of about 0.010% or less) have been found tobe equally preferred to hand-squeezed juice, when obtained from the samevariety of orange fruit (e.g. Valencia orange fruit). By comparison,current commercial feed juices have been found to be significantlydispreferred relative to hand-squeezed juice.

These "more like hand-squeezed orange juice" characteristics areimportant to the textural, aroma and flavor properties of orange juiceproducts prepared from the unique feed juices of the present invention.In addition, the particular physical and chemical composition of theseunique feed juices is highly important to subsequent processing,including aroma and flavor volatile stripping and evaporativeconcentration. Surprisingly, these high quality feed juices can beobtained at commercially acceptable juice yields (at least about 90%)when using the feed juice processing techniques to be describedhereafter. This is contrary to current belief in the orange juiceindustry that high quality feed juice can only be obtained at much lowerjuice yields and vice versa.

The unique feed juices of the present invention can be obtained fromeither Valencia orange fruit or non-Valencia orange fruit. As usedherein, "Valencia orange fruit" refers to orange fruit from the genotypeor variety Valencia which usually mature late in the respective harvestseason and typically have a relatively high peel oil content. Examplesof suitable Valencia fruit include Florida Valencia fruit, CaliforniaValencia fruit and Brazilian Valencia fruit. Juice extracted fromValencia fruit, especially Florida Valencia, tends to have a stronger"fresh" aroma/flavor character and a thinner, less pulpy texture.

As used herein, "non-Valencia orange fruit" refers to all remainingorange fruit which usually matures in the early to middle part of theharvest season and typically has a relatively low peel oil content.Examples of suitable non-Valencia fruit include the FloridaEarly/Midseason oranges (Hamlin, Parson Brown and Pineapple), Brazilianvarieties such as Pera Rio and Natal, as well as tangerines, mandarinoranges, blood oranges and navel oranges. Juice extracted fromnon-Valencia orange fruit tends to have a less strong "fresh"aroma/flavor character and a thicker, more pulpy texture compared tothat extracted from Valencia fruit.

An important characteristic of the feed juices of the present inventionis their viscosity. Selection of the "right" viscosity for the feedjuice has been found to be particularly critical to achieving a "morelike hand-squeezed juice" texture for the ultimate orange juice product.For example, orange juice products prepared from feed juices having toolow a viscosity will be characterized as "watery" or "thin" in texture.By comparison, current, higher viscosity, commercial feed juices lead toorange juice products having a "thicker" mouthfeel unlike that ofhand-squeezed orange juice. In addition, it has been found that feedjuice viscosity has important effects on juice yield and subsequentevaporative concentration of the feed juice. For example, a feed juicehaving too low a viscosity usually means an unacceptable loss of juiceyield. By contrast, a feed juice having too high a viscosity can make itextremely difficult, or impossible, to evaporatively concentrate thefeed juice and can cause excessive generation of cooked off-flavor.

For these reasons, feed juices of the present invention have relativelylow viscosities. The particular viscosity of the feed juice (whenmeasured at 8° C.) depends on the orange fruit from which it is derived.Generally, feed juices of the present invention obtained fromnon-Valencia fruit have lower viscosities than those obtained fromValencia fruit. For feed juices obtained from non-Valencia fruit, theviscosity is about 8 centipoise or less. Typically, non-Valencia feedjuices have a viscosity of from about 5 to about 8 centipoise,preferably from about 6 to about 7 centipoise. For feed juices obtainedfrom Valencia fruit, the viscosity is about 10 centipoise or less.Typically, Valencia feed juices have a viscosity of from about 7 toabout 10 centipoise, preferably from about 8 to about 9 centipoise. Feedjuices having these viscosities for the indicated orange fruit permitthe preparation of orange juice products having textural properties morelike hand-squeezed juice without significantly affecting juice yield orthe ability to effectively concentrate the feed juice by the evaporativeprocess described hereafter in part C of this application. (The methodfor measuring the viscosity of feed juices of the present invention isdescribed hereafter is part E of this application.)

Another key characteristic of feed juices of the present invention istheir level of sinking pulp. As used herein, "sinking pulp" refers toinsoluble materials present in the juice which have a particle size lessthan about 0.5 mm. Sinking pulp usually results from the shredding orcutting of juice sacs into much finer particles. The level of sinkingpulp has a particularly important effect on the viscosity of the feedjuice. Generally, as the level of sinking pulp increases, the viscosityof the feed juice likewise increases. In addition, the level of sinkingpulp can be an indicator of how gently the feed juice was extracted andfinished. Generally, the more gentle the extraction and finishing steps,the lower the level of sinking pulp. Other factors affecting the levelof sinking pulp include the condition of the fruit (especially freezedamage) and its physical handling prior to extraction.

The level of sinking pulp is desirably minimized in feed juices of thepresent invention. The particular sinking pulp level of the feed juicedepends on the orange fruit from which it is derived. Generally, feedjuices of the present invention obtained from non-Valencia fruit haveless sinking pulp than those obtained from Valencia fruit. For feedjuices obtained from non-Valencia fruit, the level of sinking pulp isabout 8% or less. Typically, non-Valencia feed juices have a sinkingpulp level of from about 5 to about 8%, preferably from about 6 to about7%. For feed juices obtained from Valencia fruit, the level of sinkingpulp is about 10% or less. Typically, Valencia feed juices have asinking pulp level of from about 7 to about 10%, preferably from about 8to about 9%. (The method for measuring the sinking pulp level of feedjuices of the present invention is described hereafter in part E of thisapplication.)

Another important characteristic of feed juices of the present inventionis their level of titratable peel oil. The level of peel oil can be animportant indicator of how carefully the juice was extracted from theorange fruit, especially fruit which has not been deoiled. Generally,the lower the level of peel oil (and other peel contaminants) present inthe feed juice, the more gentle is the extraction of the juice from theorange fruit.

It is desirable in the feed juices of the present invention to minimizethe level of titratable peel oil. The level of titratable peel oil inthese feed juices is about 0.015% or less, preferably about 0.010% orless. The particular level of titratable peel oil in these feed juicesoften depends on the fruit from which it is derived. Generally, feedjuices from non-Valencia fruit can be more easily processed to havelower levels of titratable peel oil than those obtained from Valenciafruit. For non-Valencia feed juices, the level of titratable peel oiltypically ranges from about 0.004 to about 0.010%. For Valencia juices,the level of titratable peel oil typically ranges from about 0.006 toabout 0.015%. By comparison, current commercial feed juices typicallyhave titratable peel oil contents of from about 0.020 to about 0.045%.(The method for measuring the titratable peel oil content of feed juicesof the present invention is described hereafter in part E of thisapplication.)

The level of peel oil present in the feed juice can greatly affect itsorange aroma and flavor composition, as well as that of the resultingorange juice product. The orange flavor compounds present in peel oiltend to be bitter or burning in character. During subsequent strippingof the feed juice to remove and recover orange aroma and flavorvolatiles prior to evaporative concentration, these bitter/burningflavor compounds can be removed and recovered as well. Since thestripped volatiles are subsequently added back to the concentratedjuice, this can result in undesirable bitter/burning flavorcharacteristics in the orange juice product if the level of peel oil inthe feed juice is too high. In addition, peel oil comprisespredominantly terpene (or terpene-like) compounds which can be oxidizedor thermally degraded to less desirable orange flavor compounds. Highlevels of peel oil can also adversely affect the partitioning ofdesirable water-soluble orange flavor compounds into the oil phase.

The importance of minimized peel oil content on the orange aroma andflavor quality of feed juices is particularly shown by a ratio based onthe level of more desirable orange compounds, relative to the level ofless desirable orange compounds. For the purposes of the feed juices ofthe present invention, the level of more desirable orange compounds isbased on the combined amount of acetaldehyde, methanol, ethyl butyrate,ethyl 3-hydroxyhexanoate and valencene. Acetaldehyde, methanol, ethylbutyrate and ethyl 3-hydroxyhexanoate are highly volatile compoundswhich contribute to the "freshness" of the feed juice. Valencene is aless volatile compound which contributes desirable "orangey" flavorcharacter to the feed juice.

For the purposes of the feed juices of the present invention, the levelof less desirable orange compounds is based on the combined amount ofhexanal, alpha-pinene, myrcene, decanal, linalool, and octanal. Theseless desirable compounds represent components obtained from the peelportion of the fruit, as well as undesirable degradation products.Except for hexanal, these compounds are generally less volatile thanwater.

In addition to fruit variety (non-Valencia versus Valencia fruit) andjuice processing conditions, seasonal and yearly variations in fruitlots can affect the ratio of more desirable to less desirable orangecompounds for a given feed juice. Even so, it has been found, onaverage, that feed juices of the present invention have a higher ratioof more desirable orange compounds to less desirable orange compoundswhen compared to current commercial feed juices for a given variety offruit. Conversely, it has also been found that this ratio, on average,is lower than that of hand-squeezed juice for a given variety of fruit.In addition, it has been surprisingly found that, as the level oftitratable peel oil in feed juices of the present invention is decreased(e.g., from 0.015% to 0.010%), the change in chemical composition(especially the ratio of more to less desirable compounds) is fargreater than would be expected from the decreased peel oil level.

The differences in the ratio of more to less desirable compounds(averaged over two fruit seasons±standard deviation) between feed juicesof the present invention containing moderate titratable peel oil levels(Moderate Oil) and preferred low titratable peel oil levels (Low Oil),and hand-squeezed juice (HSJ) and current commercial feed juices(Current), are particularly shown in the following Tables:

    ______________________________________                                        Florida Early/Midseason Fruit                                                        HSJ       Low Oil   Moderate Oil                                                                            Current                                  ______________________________________                                        Peel   0.0061    0.0098    0.0147    0.0228                                   Oil (%)*                                                                             ±.0027 ±.0015 ±.0012 ±.0058                                       (n = 18)  (n = 62)  (n = 53)  (n = 44)                                 Ratio* 33.79     18.07     12.66     7.00                                            ±17.45 ±9.57  ±5.15  ±4.66                                        (n = 18)  (n = 62)  (n = 53)  (n = 52)                                 ______________________________________                                        Forida Valencia Fruit                                                                HSJ       Low Oil   Moderate Oil                                                                            Current                                  ______________________________________                                        Peel   0.0044    0.0106    0.0137    0.0332                                   Oil(%)*                                                                              ±.0014 ±.0013 ±.0010 ±.0065                                       (n = 66)  (n = 116) (n = 36)  (n = 45)                                 Ratio* 49.10     18.48     12.63     5.44                                            ±19.72 ±7.68  ±4.70  ±2.13                                        (n = 67)  (n = 116) (n = 36)  (n = 45)                                 ______________________________________                                         *average based on completely finished juices                             

Certain Valencia feed juices of the present invention with ratios ofmore desirable to less desirable orange compounds of from about 8.5 toabout 21.5 have been found to be especially preferred. These preferredValencia feed juices have been found, in flavor paneling of thecompletely finished juice, to be equally preferred to certainhand-squeezed Valencia juice with ratios of from about 18 to about 52.These preferred Valencia feed juices have also been found, in flavorpaneling of the completely finished juice, generally to be significantlypreferred over current commercial Valencia feed juices with ratios offrom about 3 to about 7. (It is also expected that non-Valencia feedjuices of the present invention with ratios of more desirable to lessdesirable orange compounds of from about 8.5 to about 21.5 would providesimilar results.)

(The method used to measure the level of ethanol, methanol,acetaldehyde, ethyl butyrate and hexanal in feed juices of the presentinvention is the purge and trap analytical method described hereafter inpart E of this application. The method used to measure the level of theremaining orange compounds in feed juices of the present invention isthe tissue homogenization analytical method described hereafter in partE of this application.)

Another important characteristic of the feed juices of the presentinvention is their level of flavanoid glycosides. The most predominantexample of these glycosides is hesperidin. Hesperidin is present atsignificant levels in both the rag and the albedo portion of the peel,and at especially high levels in the pulp. Accordingly, the level offlavanoid glycosides present in the feed juice can be an indicator ofhow gentle was the extraction of the orange fruit and the finishing ofthe resulting juice. Generally, the more gently the extraction andfinishing, the lower will be the level of flavanoid glycosides in thefeed juice. In addition to indicating the gentleness of extraction andfinishing, the level of these flavanoid glycosides can affect theviscosity of the feed juice. Generally, the lower the level of theseglycosides, the lower will be the viscosity of the feed juice (i.e.,tends to parallel level of sinking pulp). Besides affecting theviscosity of the feed juice (and resulting orange juice product), highlevels of these glycosides can cause fouling of evaporators used in thesubsequent concentration step, leading to development of cookedoff-flavor.

For feed juices of the present invention, it is desirable to minimizethe level of flavanoid glycosides. The particular level of glycosides inthese feed juices depends on the fruit from which it is derived.Generally, feed juices obtained from non-Valencia fruit have higherlevels of glycosides than those obtained from Valencia fruit. Fornon-Valencia feed juice, the level of these glycosides is about 200 mg.or less per 100 ml., with a typical range of from about 125 to about 200mg. per 100 ml. For Valencia feed juices, the level of these glycosidesis about 175 mg. or less per 100 ml., with a typical range of from about100 to about 175 mg. per 100 ml. (The method for measuring the level offlavanoid glycosides in feed juices of the present invention isdescribed hereafter in part E of this application.)

The unique feed juices of the present invention are obtained by acombination of careful fruit selection and processing conditions. Thefirst step is to select processable orange fruit. As used herein, theterm "processable orange fruit" refers to fruit which can be processedwith commercial juice extraction and finishing equipment to provide feedjuices having a ratio of Brix solids to titratable acidity (TA) of fromabout 12 to about 20, preferably from about 14 to about 18. For example,soft, rotten or immature fruit are preferably removed to prevent theintroduction of undesired contaminants into the feed juice. In addition,the selected fruit is preferably processed into feed juice within about48 hours of being harvested. This minimizes the development ofoff-flavor compounds in the fruit which occurs over time, especially asthe result of abuse and damage during storage.

The selected fruit is gently extracted in a commercial juice extractorto provide extracted juice having about 0.015% or less titratable peeloil, preferably about 0.010% or less titratable peel oil. The term"gently extracted" refers to an extraction method which minimizes thelevel of peel oil in the extracted juice. Gentle extraction methods alsominimize the abrasion of rag and albedo portions of the peel whichcontain flavanoid glycosides. Further, gentle extraction methodstypically avoid significant shredding and cutting of the juice sacswhich can add significant levels of sinking pulp to the extracted juice.

The term "commercial juice extractor" refers to a mechanical juiceextractor which is capable of processing at least 200 orange fruit perminute. There are three general types of commercial juice extractors.One is referred to as a "reamer-type" juice extractor. In reamer-typejuice extractors, fruit entering the machine is sliced in half. The twohalves to opposite sides of the machine. The halves are oriented, pickedup by cups, and then positioned across serrated reamers revolving on asynchronized carrier, on a slightly inclined plane. As the fruitprogresses around the extractor turntable, the inclined plane causes therotating reamers to exert increasing pressure on the halved fruit andthus express the juice. See Nagy et al, Citrus Science and Technology,Vol. 2, (1977), pp. 192-93. Examples of suitable reamer-type juiceextractors include the Brown Model 400 (up to 350 fruit per minute), theBrown Model 700 (up to 700 fruit per minute), and the Bertuzzi ModelR-16 (up to 400 fruit per minute). See also U.S. Pat. No 3,858,500 toRohm et al, issued Jan. 7, 1975, and U.S. Pat. No. 4,421,021 toHolbrook, issued Dec. 20, 1983, for other examples of reamer-type juiceextractors.

The second type of juice extractor used in the citrus industry isreferred to as a "rotating disc-type." In a rotating disc-type juiceextractor, each fruit becomes wedged between pairs of revolving,tapered, circular rubber discs. The discs carry the fruit through asteel knife which slices the fruit in half. Each half travels aconverging path between a perforated steel grid and one of the rotatingdiscs, thus causing juice to be extracted. (The grid provides a coarseprimary finishing of the juice simultaneous with extraction.) Theextracted juice flows to the bottom of a collector where it can bedivided into a low peel oil/pulp fraction from the earlier, lighterpressure stage of extraction and a high peel oil/pulp fraction from thelater, greater pressure stage of extraction. See Nagy et al, supra, pp.194-95. Suitable rotating disc-type juice extractors include the BrownModel 1100. See also U.S. Pat. No. 3,245,339 to Leslie et al. issuedApr. 12, 1966, and U.S. Pat. No. 4,170,935 to Rohm et al, issued Oct.16, 1979, for other examples of rotating disc-type extractors.

The third type of juice extractor used in the citrus industry isreferred to as a "reciprocating cup-type." In a reciprocating cup-typeextractor, each fruit is deposited in a lower cup. The upper cup thendescends which causes the sharp upper end of a round steel tube to cut acircular hole in the bottom of the fruit. As the plurality of fingers ofthe upper and lower cups mesh, the expressed juice-laden segments passinto the tube through the hole cut in the fruit. The lower end of thetube has a restrictor to prevent the loss of juice and to force thejuice through perforations in the side of the tube. Seeds, rag, peel andlarge pulp particles remain inside the tube. See Nagy et al, supra, pp.190-191. Examples of suitable reciprocating cup-type juice extractorsinclude the FMC Model 291, the FMC Model 391, the FMC Model 491 and theFMC Model Low Oil Juice machines. See also U.S. Pat. No. 4,376,409 toBelk, issued Mar. 15, 1983, and U.S. Pat. No. 4,309,943 to Larson et al,issued Jan. 12, 1982, for other examples of reciprocating cup-type juiceextractors.

Unless the orange fruit has been de-oiled, most reamer-type, rotatingdisc-type and reciprocating cup-type juice extractors will provideextracted juice having a titratable peel oil content above about 0.015%for Valencia fruit and typically above about 0.010% for non-Valenciafruit. Accordingly, a preferred step prior to juice extraction is tode-oil fruit. De-oiling of fruit can be achieved by using a scarifierdevice. Scarifiers work by pricking the surface of the orange fruit.This permits peel oil to exude out of the fruit. The exuded peel oil canbe washed off of the fruit and removed to prevent its inclusion in theextracted juice. Suitable scarifiers for carrying out this de-oilingstep include Brown Oil Extractors, Indelicato Scarifiers or BertuzziCitro Raps.

Not all juice extractors require a prior de-oiling operation in order toprovide extracted juice having the previously specified maximum peel oilcontents. One such juice extractor is the Model Low Oil Juice machinemanufactured by FMC Corporation, Citrus Machinery Division, of Lakeland,Florida. The FMC Low Oil Juice machine is a reciprocating cup-type juiceextractor which is capable of providing extracted juice havingtitratable peel oil contents of about 0.015% or less for Valencia fruit(typically about 0.010% or less for non-Valencia fruit) without a priorde-oiling step. Extracted juice having titratable peel oil contents aslow as 0.006% can be obtained from Valencia fruit (as low as 0.004% whenobtained from non-Valencia fruit) using this Low Oil Juice machine.Accordingly, a prior de-oiling step is optional with such Low Oil Juiceextractors.

The extracted juice is partially finished by removing non-juicematerials. As used herein, the term "non-juice materials" refers to anyrag, seed or peel materials present in the extracted juice. Thesenon-juice, which are relatively large in size, are essentially the wasteproduct of juice extraction. More importantly, these non-juice materialscontain undesirable bitter flavor compounds and enzymes (e.g.,pectinesterase) which can be leached out by the extracted juice.

Accordingly, these non-juice materials need to be removed gently andquickly from the extracted juice. By "gently" is meant removal such thatthere is minimal expression of the bitter flavor compounds and enzymesfrom the nonjuice materials into the extracted juice, as well as minimalgrinding of nonjuice materials. Gentle removal methods typically impartrelatively low work-energy input to the extracted juice. By "quickly" ismeant removal of these non-juice materials before excessive amounts ofundesirable bitter flavor components and enzymes can be leached out bythe extracted juice. Generally, removal of these non-juice materialswithin about 3 minutes of juice extraction is sufficient to avoidexcessive leaching out of bitter flavor compounds and enzymes.

When a reamer-type or rotating disc-type juice extractor is used,partial finishing of the extracted juice requires the use of a primaryfinisher. Liquatex vibrating screens are particularly suitable primaryfinishers. In operation, the extracted juice is poured onto the screenof the finisher. The mesh size of the screen is such that the partiallyfinished juice passes through the screen while non-juice materials areretained on the top thereof. This screen is gently vibrated to cause thenon-juice materials to move to one side of the screen so that they canbe removed. Vibration of the screen is such that a relatively lowwork-energy input is imparted to the juice, i.e. less than 5 BTU pergallon of extracted juice, preferably less than 2 BTU per gallon ofextracted juice. This low-energy work input prevents or minimizesexpression of bitter flavor compounds and enzymes from non-juicematerials. Other primary finisher devices, such as rotating screens,which impart low-work energy input to the extracted juice can also beused instead of a vibrating screen.

Although vibrating screen primary finishers gently and quickly removenon-juice materials from the extracted juice, they also reduce theeffective yield of juice from the orange fruit. The low-work energyinput required for gentle removal of non-juice materials results infairly large amounts of desirable juice being entrained in the non-juicematerial stream. This entrained juice is usually difficult or impossibleto recover from the non-juice materials. Accordingly, for increasedjuice yield, it is preferred to use reciprocating cup-type juiceextractors. Reciprocating cup-type juice extractors do not require aprimary finisher since juice extraction and removal of non-juicematerials are carried out at the same time in about 1 second or less.This combined extraction/finishing operation prevents the entrainment ofjuice in the non-juice materials.

After non-juice materials have been removed, sensible pulp is thenremoved from the partially finished juice to provide a completelyfinished juice. As used herein, "sensible pulp" refers to insoluble pulpparticles which have a size greater than about 0.5 mm. Sensible pulp canbe removed from the partially finished juice by any suitable screw-typeor paddle-type juice finisher, or by a vibrating screen. Examples ofsuitable screw-type finishers include Brown Model 2503 and 3600 screwfinishers, FMC Model 35 screw finisher, and preferably FMC Model UCF 200"close tolerance" finishers. Examples of suitable paddle-type finishersinclude the Brown Model 200 paddle finisher. See Nagy et al, supra, atpp. 196-99.

As can be gathered from its name, sensible pulp imparts mouthfeelproperties to orange juice and is, therefore, a desirable component oforange juice products. However, in order to properly process the feedjuice, sensible pulp must be removed for at least two reasons. The firstis to prevent absorption by the pulp of desirable orange aroma andflavor compounds. Once absorbed, these compounds cannot be easilyremoved during subsequent volatile stripping of the feed juice andrepresent an essence yield loss. In addition, sensible pulp needs to beremoved from efficient evaporative concentration. Because of its size,any sensible pulp present in the feed juice can: (1) build up and plugequipment used in evaporative concentration, thus necessitating repeatedcleaning operations to remove it; and (2) affect the feed juice flowpattern through the evaporators, thus lowering the juice solids contentof the resulting concentrate or causing scorching of the juice solids.

Accordingly, the completely finished juice needs to be substantiallyfree of sensible pulp. As used herein, "substantially free of sensiblepulp" refers to a sensible pulp level of less than about 1% in thecompletely finished juice. Typically, the level of sensible pulp in thecompletely finished juice is as close to 0% as possible. A screw-type orpaddle-type finisher fitted with a 20 mesh screen will typically removeall (or almost all) of the sensible pulp. Once removed, the sensiblepulp is typically processed further (e.g. pasteurized) and stored forsubsequent inclusion in the final orange juice products.

After removal of the sensible pulp, the completely finished juice has asinking pulp level of at least about 10%. Typically, the sinking pulplevel of the completely finished juice is from about 12 to about 30%.The viscosity of this completely finished juice is at least about 10centipoise, and is typically from about 12 to about 30 centipoise. Thisviscosity needs to be somewhat lower for efficient evaporativeconcentration of the feed juice, as well as to provide orange juiceproducts having a texture/mouthfeel which more closely approacheshand-squeezed orange juice.

To lower the viscosity of the completely finished juice, at least someof the sinking pulp is removed. The amount of sinking pulp removed issuch that the resulting feed juice has sinking pulp level of about 8% orless (typical range of from about 5 to about 8%) for non-Valencia fruitand about 10% or less (typical range of from about 7 to about 10%) forValencia fruit. This also results in the feed juice having a viscosityof about 8 centipoise or less (typical range of from about 5 to about 8centipoise) for non-Valencia fruit and about 10 centipoise or less(typical range of from about 7 to about 10 centipoise) for Valenciafruit. Removal of sinking pulp from the completely finished juice istypically achieved by using centrifugation. However, other separationmethods involving filters, juice finishers, belt presses and stationaryscreens can also be used to remove a portion of the sinking pulp fromthe completely finished juice to provide the feed juices of the presentinvention.

Surprisingly, the high quality feed juices of the present invention canbe obtained at commercially useful juice yields. This is particularlytrue if reciprocating cup-type juice extractors are used. When suchextractors are used, the feed juice of the present invention can beobtained at juice yields of at least about 90%. In particular, juiceyields of from about 92 to about 95% are achievable when the FMC Low OilJuice machine is used. (Under the definition below, it is possible tohave juice yields in excess of 100%)

For the method of the present invention, "juice yield" is based on thetotal amount of juice solids obtained per box of orange fruit (processedjuice solids yield), relative to the amount of juice solids obtained perbox of orange fruit by using a "state test" juice extractor ("state"juice solids yield) as specified in Florida regulation 20-63.001. Inother words, the juice yield can be obtained by the following equation:

    % juice yield=100% x (processed juice solids yield)/("state" juice solids yield)

where processed juice solids yield=juice yield (per box) from process xsolids content (°Brix) of juice, and

where "state" juice solids yield=juice yield (per box) from "state test"extractor x solids content (°Brix) of juice.

Reciprocating cup-type juice extractors are also desirable in terms ofincreasing the yield of sensible pulp compared to reamer-type androtating disc-type extractors. The primary finisher required to removenon-juice materials when a reamer-type or rotating disc-type juiceextractor is used diminishes not only the juice yield but also the yieldof sensible pulp. Accordingly, use of reciprocating cup-type extractorsto obtain feed juices of the present invention provides an optimumcombination of juice yield and sensible pulp yield.

The feed juices of the present invention are particularly useful in thearoma/flavor volatile stripping and evaporative concentration processesdescribed hereafter in parts B and C of this application. However, thesefeed juices are also suitable for freeze concentration processes becauseof their relatively low viscosity and titratable peel oil content, andgood orange aroma/flavor character. See U.S. Pat. No. 4,374,865 toStrobel, issued Feb. 22, 1983, for a suitable freeze concentrationprocess.

The following are representative examples of feed juices obtainedaccording to the present invention.

EXAMPLE 1

California Valencia packinghouse orange fruit having a size ranging from21/4to 3 inches were randomized and thoroughly washed to remove waxesprior to juice extraction. The washed fruit was extracted by using aBrown Model 400 juice extractor. The extractor was set to operate at 1/8in. peel clearance, with a soft plastic cup-type and an extractionpressure of 20 psig. Approximately 350 fruit per minute were processedby this extractor.

Sensible pulp, membrane and seeds were removed from the extracted juiceby passing it over a 4 sq. ft. Liquatex vibrating screen which had meshopenings of 0.066 in.

The resulting completely finished juice had the following physical andchemical characteristics:

    ______________________________________                                        °Brix        13.7                                                      Titratable acidity (%)                                                                            0.85                                                      Peel oil (%)        0.012                                                     Glycosides (mg/100 ml)                                                                            137                                                       Sinking pulp (%)    16                                                        Flavor composition (ppb)                                                      Ethanol             287,400                                                   Acetaldehyde        9700                                                      Methanol            24,500                                                    Ethyl butyrate      150                                                       Ethyl 3-hydroxyhexanoate                                                                          601                                                       Valencene           8696                                                      Hexanal             250                                                       alpha-Pinene        407                                                       Myrcene             2048                                                      Decanal             337                                                       Linalool            475                                                       Octanal             0                                                         Ratio of more to less                                                                             12.48                                                     desirable compounds                                                           ______________________________________                                    

This completely finished juice can be passed through a desludgercentrifuge operated at 1000 to 3000 g force to remove additional sinkingpulp so as to provide a feed juice having a viscosity of about 10centipoise or less and a sinking pulp level of about 10% or less.

EXAMPLE 2

Florida Pineapple orange fruit having a diameter of 27/80 inches or lesswere thoroughly washed prior to juice extraction. The washed fruit wasextracted by using an FMC Model Low Oil juice machine.

Sensible pulp was removed from the extracted juice by passing it throughan FMC Model 35 screw finisher having a 20 mesh screen (i.e. 0.020 in.openings) and a pressure setting of 20 psig.

The resulting completely finished juice had the following physical andchemical characteristics:

    ______________________________________                                        °Brix        12.2                                                      Titratable acidity (%)                                                                            0.69                                                      Peel oil (%)        0.010                                                     Glycosides (mg/100 ml)                                                                            151                                                       Sinking pulp (%)    17                                                        Flavor composition (ppb)                                                      Ethanol             408,760                                                   Acetaldehyde        5530                                                      Methanol            32,550                                                    Ethyl butyrate      9.0                                                       Ethyl 3-hydroxyhexanoate                                                                          3127                                                      Valencene           21,094                                                    Hexanal             27                                                        alpha-Pinene        691                                                       Myrcene             2487                                                      Decanal             278                                                       Linalool            195                                                       Octanal             0                                                         Ratio of more to less                                                                             16.94                                                     desirable compounds                                                           ______________________________________                                    

This completely finished juice can be passed through a desludgercentrifuge operated at 1000 to 3000 g force to remove additional sinkingpulp so as to provide a feed juice having a viscosity of about 8centipoise or less and a sinking pulp level of about 8% or less.

EXAMPLE 3

California Valencia orange fruit was randomized with decayed fruit beingremoved prior to deoiling. A Bertuzzi Citrorap CI 33/6 deoiler was setup with approximately 85°-90° F. rinse water sprays, rasping rolls at amaximum speed of 300 rpm, and a feed auger speed of 8 rpm. An FMC Model291 juice extractor (500 fruit processed per minute) was also used withthe following machine settings:

    ______________________________________                                        Cups              3 inch standard                                             Peel clearance    10/64 inch                                                  Restrictor        7/16 inch long bore                                         Strainer tube     0.040 inch                                                  Orifice tube      1 inch                                                      Beam setting      3/4 inch                                                    ______________________________________                                    

Two and one-half boxes of the washed oranges were dumped slowly into thedeoiler and then collected in a strainer basket. A portion of thesedeoiled oranges were used to prime the extractor, with the extractedjuice being discarded. An additional 60 lbs. of deoiled fruit was thenextracted. This extracted juice had a titratable peel oil content of0.013%. This juice can be passed through a Model 35 screw finisherhaving a 20 mesh screen and a pressure setting of 20 psig to provide acompletely finished juice. This completely finished juice can then bepassed through a desludger centrifuge operated at 1000 to 3000 g forceto remove additional sinking pulp so as to provide a feed juice having aviscosity of about 10 centipoise or less and a sinking pulp level ofabout 10% or less.

EXAMPLE 4

Florida Valencia orange fruit having a diameter of 27/8 inches or lesswere throughly washed prior to juice extraction. The juice was extractedusing an FMC Model Low Oil juice machine. The extracted juice was passedthrough an FMC UCF 200 finisher having a 20 mesh screen at a pressuresetting of 20 psig.

The resulting completely finished juice had the following physical andchemical characteristic:

    ______________________________________                                        °Brix        11.9                                                      Titratable acidity (%)                                                                            0.81                                                      Peel oil (%)        0.011                                                     Glycosides (mg/100 ml)                                                                            126                                                       Sinking pulp (%)    13                                                        Viscosity (cps)     14.1                                                      Flavor composition (ppb)                                                      Ethanol             338,150                                                   Acetaldehyde        5900                                                      Methanol            30,200                                                    Ethyl butyrate      350                                                       Ethyl 3-hydroxyhexanoate                                                                          --                                                        Valencene           14,081                                                    Hexanal             50                                                        alpha-Pinene        505                                                       Myrcene             1998                                                      Decanal             95                                                        Linalool            413                                                       Octanal             0                                                         Ratio of more to less                                                                             16.51                                                     desirable compounds                                                           ______________________________________                                    

This completely finished juice can be passed through a desludgercentrifuge operated at 1000 to 3000 g force to remove additional sinkingpulp so as to provide a feed juice having a viscosity of about 10centipoise or less and a sinking pulp level of about 10% or less.

EXAMPLE 5

Process grade Hamlin orange fruit which had been stored forapproximately 24 hours prior to extraction was used. Several bins offruit were blended to achieve a nominal 15 Brix/Acid ratio average. Theblended fruit was washed with CS-100 at 100 ppm followed by a freshwater rinse. The cleaned fruit was visually inspected and gradedimmediately prior to extraction. After grading, the fruit exhibited lessthan 2% decay and 10% unwholesome defects.

The fruit was split into two size ranges. Small fruit (less than 3inches in diameter) was fed to a first set of FMC Low Oil Juiceextractors. Large fruit (greater than 3 inches) was fed to a second setof FMC Low Oil Juice extractors.

Extracted juice, containing sensible pulp and seed defects, wascollected in an enclosed manifold and surged into a feed tank. Thisjuice was then pumped through hydro-clone deseeders operating at anominal 75 psig back pressure to remove immature seed defects. The juicethen was passed through a FMC UCF 200 finisher, operating with a 0.020inch screen and 5 psig back pressure, to remove sensible pulp.

The pulp-free juice was surged into a level controlled tank prior tocentrifugation. Westfalia SB-80 desludger centrifuges, operating at 3000g force, removed sinking pulp from the juice stream. Feed rate and shotcycle times were adjusted to achieve desired viscosity reduction in thefeed juice.

The feed juice was compared to hand-squeezed juice prepared fromidentical oranges which had been cut in half, reamed gently on an Osterjuicer and hand sieved through a 20 mesh screen. Analytical results ofthis comparison are shown below:

    ______________________________________                                                    Hand-Squeezed                                                                           Feed Juice of                                                       Juice     Present Invention                                       ______________________________________                                        Brix°  10.23       10.63                                               Titratable    0.68        0.69                                                Acidity (%)                                                                   Brix/Acid Ratio                                                                             15.0        15.4                                                Oil (%)       0.0028      0.0052                                              Sinking Pulp (%)                                                                            13          6                                                   Viscosity (cps)                                                                             9.0         5.2                                                 Ratio of More to                                                                            57.67       23.15                                               Less Desirable                                                                Compounds                                                                     ______________________________________                                    

B. Obtaining Aqueous Stripper Essence and Stripper Oil from Feed Juice

Another key aspect of the present invention is to preserve the moredesirable orange aroma and flavor compounds present in the feed juicewithout generating additional less desirable orange aroma and flavorcompounds. The characteristic "fresh" compounds present in the feedjuice include the low molecular weight alcohols (e.g. ethanol andmethanol), aldehydes (e.g. acetaldehyde) and esters (e.g. ethyl butyrateand ethyl acetate). Since these "fresh" compounds are low-boiling, theycan be easily lost due to volatilization. In addition, these low-boilingcompounds, as well as certain desirable high-boiling compounds such asvalencene are easily degraded during evaporative heat concentration ofthe feed juice. This typically leads to greater concentrations of lessdesirable orange aroma and flavor compounds such as linalool andalpha-terpineol.

The basic method for preserving these more desirable orange aroma andflavor compounds is disclosed in European patent application No. 110,638to Powers et al, published June 13, 1984, which is incorporated byreference. The Powers et al process generally involves the following:(1) removal of orange aroma/flavor volatiles from the feed juice; and(2) recovering these volatiles in the form of an orange aroma/flavorcondensate which is separated to provide an aqueous orange stripperessence and an orange stripper oil. The details of this process and theresulting stripper essence and stripper oil obtained are as follows:

1. Removal of Volatiles

The feed juice is passed through a device such as a heat exchanger toquickly raise the temperature of the juice to the feed temperature ofthe stripping column.

This temperature ranges from about 100° F. (37.7° C.) to about 160° F.(71° C.); preferably temperatures of from 125° F. (51.7° C.) to 140° F.(60° C.) are used. Any suitable means can be used to heat the feedjuice, e.g. shell and tube, plate or spiral heat exchangers or directsteam injection. Either low pressure steam or hot water can be used asthe heating medium in the heat exchangers.

The hot feed juice is then pumped into the top of a stripper columnwhich is operated under vacuum. The stripper column can consist of avertical cylindrical vessel encompassing one or more stripping stages.Each stage consists of a means for distributing a fine spray of juicedroplets across the whole circular cross section of the vessel. Thejuice is atomized so that the entire cross section of the column iscovered with atomized juice droplets. This can be accomplished withpressure atomizing nozzles or by other means such as two-fluid nozzlesor spinning disk atomizers. Either hollow or solid cone sprays can beproduced.

The juice is contacted with a stripping agent such as steam, or an inertgas, i.e., nitrogen or carbon dioxide, to remove or strip away the aromaand flavor volatiles. Steam is preferred for this purpose because manyof the volatiles are soluble in or co-distill with water and are thuseasily removed. Condensation of the aroma and flavor volatiles is alsoeasier to accomplish.

Stream or inert gas is introduced through the bottom of the strippercolumn. In general, from about 0.3 lbs. to about 1.5 lbs. of steam areused per each pound of soluble solids in the juice. Preferably, from 0.6to 1.0 lbs. of steam per lb. of solids are used. Cut rate is defined asthe pounds of steam per pound of soluble solids in the juice.

It is important that the vapor rising in the stripper column mix wellwith the feed juice spray, especially in the region near the nozzle sothat the volatilized aromatic material can be carried away as part ofthe vapor stream. The partially or completely stripped feed juice iscollected and pumped from the bottom of each stage. For the top stageand any intermediate stages, the feed juice is collected on a trayhaving a number of openings in it to allow for the vapor from the stagebelow to pass up the column and mix with the spray in each stage. Theopening should be covered to prevent feed juice spray from passingdirectly into the stage below. Trays should be designed to minimize thefeed juice holdup so that the overall exposure time of the feed juice tothe 100° F. (37.7° C.) to 160° F. (71° C.) temperatures can beminimized. As feed juice is pumped from one stage to another, it can beheated by the use of heat exchangers or live steam injection to atemperature above the equilibrium temperature in the stripper column sothat the feed juice flashes as it leaves the spray nozzles in thatstage. In general, the feed juice should not be heated above 160° F.(71° C.) for longer than a few seconds.

The quantity of volatile components removed can be increased byincreasing either the cut rate, the number of stages or the length ofeach stage. The amount of additional volatiles removed by increasing thecut rate above about 0.8 or 0.9 is usually small and must be balancedagainst the higher cost to remove the additional water condensed withthe volatiles. Similarly, increasing the number of stages beyond 4 or 5does not result in large increases in the amount of volatiles removed.The additional residence time of the feed juice at elevated temperaturecan result in the creation of off-flavors in the feed juice. Thus, thecut rate and the number of stages used can be varied to obtain theoptimum balance of cost, volatile removal, and minimum degradation.

Care must be taken so that the steam does not impact on the surface ofany feed juice that may be collected at the bottom of the strippercolumn. Water vapor from the added low pressure steam is passedcountercurrently through the juice spray to help remove and carry offthe volatile materials as the vapor passes upward through each stage andout of the stripper column. In addition to steam, inert gases can alsobe used to strip the feed juices. Steam is preferred because the laterconcentration step removes water in its essentially pure form. Whenother inert gases are used, they must be separated from the volatilesusing pressure equilibration techniques. These processes can cause lossof some of the aroma and flavor volatiles due to their high volatility.

The temperatures in the stripping stages can be from about 100° F.(37.7° C.) to about 160° F. (71° C.). Temperatures above 160° F. (71°C.) cause some degradation of the aroma and flavor of the juice.Preferably, the temperatures will be about 125° F. (51.7° C.) to about140° F. (60° C.). Each stage can be operated at a different temperature.The temperatures can be progressively higher in each stage, or the samein all stages.

The pressure within the stripping column can be up to 9 inches of Hg.absolute and preferably is from about 2 to about 6 inches of mercuryabsolute. Most preferably, the stripping is carried out at pressures offrom 3 to 5 inches of mercury absolute.

The stripped feed juice is pumped from the last stage and is either sentdirectly to the evaporation concentration system or else cooled andstored prior to evaporative concentration. If the juice is cooled,energy can be saved if the hot juice is used to partially heat theincoming juice. It, in turn, is partially cooled.

2. Recovery of Stripped Volatiles

The stripped aroma and flavor volatiles are passed through a demister atthe top of the stripper column and recovered by condensation attemperatures of from about 105° F. (40.6° C.) to about -320° F. (-196°C.). The actual temperature of condensation will depend upon thepressure within the condensation system. While the majority of thestripper volatile compounds in orange juice condense around -50° F.(-45.5° C.) at pressures of 2 to 9 inches of mercury absolute, condensertemperatures from about -60° F. (-51° C.) to about -320° F. (-196° C.)are sufficient to condense substantially all of the stripped aroma andflavor volatiles at low pressures.

The condensation can be carried out using shell and tube heatexchangers, condensing in vertical tubes for the liquid condensing, andin the shell of a U-tube exchanger for freezing the condensate. Theliquid condensing can also be accomplished in two or more condensers inseries using cooling tower water for the first condenser andrefrigerated coolant on subsequent condensers. Refrigerated coolantssuch as glycol and Freon can be used. Steam ejectors, mechanical vacuumpumps, or some combination can be used to reduce the pressure and removenon-condensables.

The aroma and flavor volatiles which have been gently removed from thefeed juice by stripping are preferably condensed in three stages. Thefirst stage condenses primarily the water and some of the aroma andflavor volatiles; the second and third stages condense the remainingvolatiles. The first stage condenser can be at a temperature of fromabout 60° F. (15.6° C.) to about 105° F. (40.6° C.), and preferably from60° F. (15.6° C.) to 80° F. (26.7° C.). The second stage condenser canbe at a temperature of from about 33° F. (0.5° C.) to about 60° F.(15.6° C.) and preferably from about 40° F. (4° C.) to about 50° F. (10°C.). This will insure collection of most of the water and the lessvolatile aroma and flavor materials (i.e. higher boiling compounds). Thethird condenser is at about -50° F. (-45.5° C.), and can be as low asliquid nitrogen temperatures (-320° F.). The aroma and flavor volatilesare condensed or collected as a frost in this third condenser. Thecollection efficiency of these low temperature condensers can beimproved by pre-frosting the condensing surface using steam or asteam-noncondensable gas mixture. This provides more condensation sitesfor collection of the volatile mixture.

Care must be taken to avoid losing the volatiles which are condensed asthe frost when the frost is added back to the liquid portion of thecondensate. One way to accomplish this recombination is to collect thefrozen portion on one condenser. After collecting the frost, thecondenser is isolated from the vapor system and from the vacuum systemand then filled with liquid condensate from the first condenser. Thisliquid can then be recirculated through the cryogenic condenser to meltthe frost. The temperature of this melting should be at about 35° F. (1°C.) to about 45° F. (7° C.) so that the volatiles dissolve directly into the cold liquid and do not have an opportunity to volatilize.

The liquid ring vacuum seal pump can be used in place of the thirdcondenser to recover low-boiling aroma and flavor volatiles. This typeof vacuum pump includes a liquid seal formed by water or aqueousstripper essence which is in direct contact with the volatile stream.This liquid seal is sufficiently cool to condense and then absorb thearoma and flavor volatiles in the stream. This volatile-enriched sealwater can be used, as is, to provide an aroma/flavor condensate, or elsea portion thereof can be recycled to the stripper column, as describedhereafter.

The condensate is a mixture of water-soluble volatiles such as ethanol,methanol, acetaldehyde, ethyl butyrate and ethyl acetate and oilvolatiles such as valencene, d-limonene, myrcene, and alpha-pinene whichare relatively insoluble in water. These volatile materials are presentin a relatively stable emulsion of oil in water. Some oil may separate.The oil and aqueous phases can be separated by holding cold for longperiods of time, by freezing and thawing, or preferably by centrifugingin a continuous stacked disc hermetic centrifuge. Two clear phases areobtained: (1) an aqueous stripper essence which is nearly free of oilcomponents; and (2) a stripper oil. Small quantities of a wax-likesubstance collect in the centrifuge and must be removed periodically.

The aqueous stripper essence and stripper oil are stored in closed tankswith an inert gas blanket and are preferably shielded from light toprevent oxidation of the aroma and flavor compounds. The aqueousstripper essence can be stored at cool temperatures (e.g. 40° F. (4.4°C.) or less) prior to use. The stripper oil can be stored at lowtemperatures (-10° F. (-23.3° C.)) prior to use.

Preferably, part of the condensate from the first condenser (or fromvolatile-enriched seal water) is recycled to the top of the strippercolumn. This recycle stream can be heated or cooled in a heat exchangerto the desired temperature. Preferably the temperature is within about20° F. (11° C.) of the water temperature corresponding to theequilibrium temperature of water at the pressure used in the strippercolumn. In the top of the stripper column, the recycled condensate isdistributed over packing material incorporated within the top of thecolumn. Most types of mass transfer packing can be used, such as Berlsaddles, Raschig rings, or preferably Goodloe-type wire mesh packing.Enough packing to give the equivalent of 0.5 to 3.0 theoretical transferunits may be used. Preferably this would be packing equivalent to about2 transfer units.

This recycle (rectification) process can be used to remove from 10% toup to 95% of the condensed water from the volatile stream (preferably upto 90% or 95%) without significant losses of volatile materials in thejuice going out the bottom of the stripper column. This recycling servesto concentrate the aroma and flavor volatiles portion of the aqueousstripper essence.

The vacuum system used for the stripper column can be any commercialsystem capable of achieving the desired pressures, including multi-stagesteam ejectors, vacuum pumps, or combinations. A liquid ring vacuum pumpis preferred and a preferred type is one made with stainless steel whichis a "sanitary" design. When this type of vacuum pump is used, the sealwater can be added to the aqueous stripper essence or is recycled to thestripper column, as previously described, to recover additional smallquantities of valuable volatile components. IN addition a small packedcolumn scrubber can be used after the liquid ring vacuum pump to removevirtually all of the valuable volatile materials from the exiting gasstream. When the scrubber is used, the cold water (or other liquid) usedas the scrubbing fluid can also be used as the seal fluid for the liquidring vacuum pump in a countercurrent fashion.

3. Aqueous Stripper Essence and Stripper Oil

One product resulting from the previously described volatile strippingand recovery process is a unique aqueous orange essence. This stripperessence is characterized by a relatively high level of ethanol. Thelevel of ethanol is a fairly good indicator of the concentration of"fresh" compounds in the stripper essence. Generally, the higher thelevel of ethanol, the more "fresh" compounds will be present in thestripper essence. Stripper essences of the present invention comprisefrom about 0.5 to about 8% ethanol. Typically, stripper essences of thepresent invention comprise from about 1 to about 3% ethanol.

The stripper essence of the present invention is further characterizedby a mixture of more desirable orange flavor compounds. For the purposesof the present invention, this mixture is defined by the combined amountof ethyl acetate, ethyl butyrate, and acetaldehyde present in thestripper essence. Stripper essences of the present invention comprisefrom about 100 to about 300 parts combined of ethyl acetate, ethylbutyrate and acetaldehyde, per 10,000 parts ethanol. Typically, thesestripper essences comprise from about 100 to about 200 parts combined ofethyl acetate, ethyl butyrate and acetaldehyde, per 10,000 partsethanol.

The stripper essence of the present invention is further characterizedby a mixture of less desirable orange flavor compounds. For the purposesof the present invention, this mixture is defined by the combined amountof hexanal and alpha-terpineol present in the stripper essence. Stripperessences of the present invention comprise from about 1 to about 10parts combined of hexanal and alpha-terpineol, per 10,000 parts ethanol.Preferably, these stripper essences comprise from about 1 to about 5parts combined of hexanal and alpha-terpineol, per 10,000 parts ethanol.

The stripper essence of the present invention is particularlycharacterized by a high ratio of more desirable orange flavor compounds(based on the combined amount of ethyl acetate, ethyl butyrate, andacetaldehyde) to less desirable orange flavor compounds (based on thecombined amount of hexanal, and alpha-terpineol). This ratio is fromabout 10:1 to about 300:1, typically from about 35:1 to about 80:1.Preferred stripper essences have ratios of ethyl butyrate to combinedhexanal/alpha-terpineol of from about 2:1 to about 5:1, and ethylbutyrate to hexanal of from about 3:1 to about 7:1. This high ratio ofmore desirable to less desirable compounds reflects the high quality ofthe feed juice used, as well as the preservation of the more desirableorange flavor compounds during volatile stripping and recovery. (Themethod for measuring the levels of ethanol, ethyl acetate, ethylbutyrate, acetaldehyde, hexanal and alpha-terpineol is describedhereafter in the stripper essence analytical method section of part E ofthis application.)

The previously described volatile stripping and recovery process alsoprovides a unique orange stripper oil. This stripper oil ischaracterized by its limonene content. Limonene is the predominantcomponent of these stripper oils. Stripper oils of the present inventioncomprise from about 60 to about 90% limonene. Typical stripper oilscomprise from about 65 to about 85% limonene.

The stripper oil of the present invention is further characterized by afairly high level of valencene. Valencene provides a distinct "orangey"note to the stripper oil. Stripper oils of the present inventioncomprise from about 1 to about 15 parts valencene, per 100 partslimonene. Typical stripper oils comprise from about 3 to about 10 partsvalencene, per 100 parts limonene.

The stripper oil of the present invention is further characterized by amixture of less desirable orange flavor compounds. This mixture isdefined by the combined amount of alpha-pinene, myrcene, octanal,decanal, and linalool present in the stripper oil. The combined amountof these five compounds is from about 1 to about 6 parts, per 100 partslimonene, for stripper oils of the present invention. Preferably, thecombined amount of these five compounds is from about 1 to about 4parts, per 100 parts limonene.

In particular, the stripper oil of the present invention ischaracterized by a high ratio of valencene to the combined amount ofthese five less desirable orange compounds. This ratio is from about0.5:1 to about 15:1, typically from about 0.5:1 to about 3:1. Typicalstripper oils have ratios of valencene to combined alpha-pinene andmyrcene of from about 1:1 to about 6:1 (typically from about 1:1 toabout 4:1) and valencene to combined octanal and decanal of from about2:1 to about 10:1 (typically from about 2:1 to about 5:1. Like thestripper essence, this high ratio of valencene to less desirablecompounds for the stripper oils of the present invention reflects thehigh quality of the feed juice used, as well as the preservation ofvalencene during volatile stripping and recovery. (The method formeasuring limonene, valencene, alpha-pinene, myrcene, octanal, decanaland linalool is described hereafter in the stripper oil analyticalmethod section of part E of this application.)

The following are representative examples of aqueous stripper essencesand stripper oils according to the present invention:

EXAMPLE 1

A feed juice was obtained from Florida Early/Midseason orange fruitusing a Brown 400 juice extractor and juice processing conditionssimilar to those of Example 1 of part A of this application. ThisFlorida Early/Midseason feed juice was pumped at the rate of 1800lbs./hr. (818 kg./hr.) to a four-stage production stripper column. Thecolumn was 40 ft. (12 m.) long with an inside diameter of 24 in. (61cm.). The column was operated under a vacuum of 3.5 in. (89 mm.) Hg(absolute).

The feed juice was initially heated to 126° F. (52.2° C.) beforeentering the first stage where it was sprayed into the stripper columnthrough BETE FOG Model TFIY-FCN type nozzles. Since the juice wasslightly above the equilibrium temperature and since it contained somedissolved air which would come out of solution, the expanding releasedair and small quantities of flashed water vapor caused the juice comingfrom the nozzles to be sprayed, the spray covering the entire crosssection of the stripper column. Juice was collected from the first trayand pumped through a pipeline containing a direct injection steam nozzlewhere it was reheated to 128° F. (53.3° C.) and resprayed through thesame type of nozzles as in the first stage. Juice was collected from thesecond tray and then pumped through a pipeline containing a directinjection steam nozzle where it was reheated to a temperature of 129° F.(53.9° C.) and resprayed, as in the second stage. Juice from the thirdtray was pumped through a pipeline containing a direct injection steamnozzle where it was reheated to a temperature of 145° F. (62.8° C.) andflashed into the stripper column as in the first stage. Juice collectedfrom the bottom of the stripper column was pumped through a plate andframe heat exchanger to be cooled to a temperature of 125° F. (51.7° C.)by the incoming feed juice before being pumped to an evaporator feedtank for further processing.

Culinary steam was sparged into the stripper column near the bottom, ata rate which when combined with all of the flashed vapor would give acut rate of 0.8 lbs. steam/lb. of sugar solids. Since the FloridaEarly/Midseason feed juice in this example had a juice solids content of11.3° Brix, the total steam flow rate was 161 lbs./hr. (73.2 kg./hr.).

The vapors generated passed through a stainless steel wire gauze misteliminator and about 3 ft. (0.9 m.) of Goodloe-type wire gauze typepacking to a two-stage shell and tube condensor. The first stage wascooled with cooling tower water at about 64° F. (17.8° C.) while thesecond stage was cooled using 40° F. (4.4° C.) glycol. The condensatefrom the first stage was cooled to about 48° F. (8.9° C.) by passing itthrough a shell and tube heat exchanger cooled with 40° F. (4.4° C.)glycol. This condensate was then passed through a DeLaval 194F hermeticcentrifuge to remove stripper oil. Seventy-five percent of this oil-freecondensate was recycled by pumping it through a shell and tube heatexchanger to heat it to 126° F. (52.2° C.) and then spraying it throughBETE FOG Model TFIY-FCN-type nozzles at the top of the stripper columnso that it passed through the Goodloe-type wire gauze. The remaining 25%of this condensate was collected in a cold wall condensate collectiontank and blanketed with nitrogen gas. The condensate from the secondcondenser was cooled to 48° F. (8.9° C.) by passing it through a shelland tube heat exchanger cooled with 40° F. (4.4° C.) glycol. This secondcondensate was added to the condensate collection tank.

The remaining vapors from the second stage were pulled through one oftwo shell and tube heat exchanger units which formed the third stagecondensor. The vapors were condensed as a frost in the first unit bycooling it with liquid ammonia at about -60° F. (-51.1° C.). The flow ofliquid ammonia was then stopped and the first unit was isolated from thevapor flow. The second unit was then brought on line to receive thevapor flow and condense the vapors as frost, as in the case of the firstunit. The first unit was then warmed to about 40° F. (4.4° C.) withliquid ammonia with the frost being dissolved and removed by pumpingthrough condensate from the collection tank. The two units werealternated in this vapor condensation/frost removal cycle at about 1hour intervals.

The remaining vapors from the third stage condensor were then passedthrough a vacuum pump. Most of the vapor discharged from the vacuum pumpwas recycled back to the third stage condensor. The remainingnoncondensible vapors were discharged to the atmosphere.

The condensate from the collection tank was pumped through a DeLaval194F hermetic centrifuge at a rate of about 2 gpm. The centrifugecontinuously separated the condensate into two clear streams. Thestripper oil was taken off as the light component and collected (alongwith stripper oil from the recycled condensate) under nitrogen gas in a55 gallon (208 1.) stainless steel drum. These drums were stored at 0°F. (-17.8° C.). The heavier aqueous stripper essence was pumped to acold wall storage tank and held at 40° F. (4.4° C.) under nitrogen.

The aqueous stripper essence was found to have the following compositionafter gas chromatographic analysis (see Part E of this application):

    ______________________________________                                                                 Parts per 10,000                                     Compound     Amount (ppm)                                                                              Parts Ethanol                                        ______________________________________                                        Ethanol      14,601      --                                                   Acetaldehyde 186.0       127.4                                                Ethyl acetate                                                                              13.15       9.01                                                 Ethyl butyrate                                                                             17.01       11.65                                                Hexanal      3.11        2.13                                                 alpha-Terpineol                                                                            2.93        2.01                                                 ______________________________________                                    

The stripper oil obtained was found to have the following compositionafter gas chromatographic analysis (see part E of this application):

    ______________________________________                                                                 Parts per 100                                        Compound    Amount (mg./ml.)                                                                           Parts Limonene                                       ______________________________________                                        Limonene    776.18       --                                                   Valencene   25.08        3.23                                                 alpha-Pinene                                                                              2.57         0.33                                                 Myrcene     13.97        1.80                                                 Octanal     1.86         0.24                                                 Decana-     3.04         0.39                                                 Linalool    0.96         0.12                                                 ______________________________________                                    

EXAMPLE 2

A feed juice was obtained from Florida Valencia orange fruit using anFMC Low Oil juice extractor and juice processing conditions similar tothose of Example 2 of part A of this application. This Florida Valenciafeed juice (12.9° Brix) was pumped at the rate of 1600 lbs./hr. (727Kg./hr.) to a four-stage stripper column as in Example 1. The operatingconditions for this column were as follows:

    ______________________________________                                        First stage temp.                                                                              131° F. (55° C.)                               Second stage temp.                                                                             133° F. (56.1° C.)                             Third stage temp.                                                                              124° F. (51.1° C.)                             Fourth stage temp.                                                                             125° F. (51.7° C.)                             Bottoms temp.    125° F. (51.7° C.)                             Vacuum           3.5 in. (89 mm) Hg absolute                                  Cut rate         0.8 lbs. steam/lb sugar solids                               Steam flow rate  165 lbs./hr. (75 kg./hr)                                     ______________________________________                                    

The vapors generated from the stripper column were passed through themist eliminator and wire gauze packing to a two-stage shell and tubecondensor as in Example 1. The first stage was cooled with cooling towerwater at about 71° F. (21.7° C.) while the second stage was cooled using40° F. (4.4° C.) glycol. Seventy-five percent of the condensate from thefirst stage was recycled by cooling and removing stripper oil from it asin Example 1, heating it to 130° F. (54.4° C.) and then spraying itthrough the top of the stripper column as in Example 1. The remaining25% of the condensate from the first stage, as well as the condensatefrom the second stage, were collected in the collection tank, as inExample 1.

The remaining vapors from the second stage were passed through a vacuumpump. The vapors discharged from the vacuum pump were bubbled throughthe condensate in the collection tank. The collected condensate wasseparated into an aqueous stripper essence and stripper oil as inExample 1.

The aqueous stripper essence was found to have the following compositionafter gas chromatographic analysis (see part E of the application):

    ______________________________________                                                                 Parts per 10,000                                     Compound     Amount (ppm)                                                                              Parts Ethanol                                        ______________________________________                                        Ethanol      15,744      --                                                   Acetaldehyde 215.0       136.6                                                Ethyl acetate                                                                              14.11       8.96                                                 Ethyl butyrate                                                                             13.07       8.30                                                 Hexanal      2.56        1.63                                                 alpha-Terpineol                                                                            0.89        0.56                                                 ______________________________________                                    

The stripper oil obtained was found to have the following compositionafter gas chromatographic analysis (see part E of this application):

    ______________________________________                                                                 Parts per 100                                        Compound    Amount (mg./ml.)                                                                           Parts Limonene                                       ______________________________________                                        Limonene    694.49       --                                                   Valencene   59.86        8.62                                                 alpha-Pinene                                                                              2.41         0.35                                                 Myrcene     12.34        1.78                                                 Octanal     1.67         0.24                                                 Decanal     5.07         0.73                                                 Linalool    0.60         0.09                                                 ______________________________________                                    

C. Evaporative Concentration of Feed Juice

The feed juice (as is or stripped of aroma/flavor volatiles according topart B of this application) is evaporatively concentrated to provide anorange juice concentrate having a high juice solids content as measuredby the Brix value. The primary function of evaporative concentration isto remove water from the feed juice. However, evaporative concentrationcan also perform the additional function of deactivating pectinesteraseenzymes present in the feed juice. This prevents or greatly reducesdemethoxylation of pectin in the juice and subsequent undesirablejellification in the orange juice concentrate.

The heating which occurs during evaporative concentration can cause theoxidation and degradation of any orange aroma and flavor compounds whichremain in the feed juice. This can result in the generation of undesiredcooked off-flavor. In addition, heating the juice during evaporativeconcentration to too high a temperature for too long a period of timecan greatly increase the viscosity of the resulting orange juiceconcentrate. Accordingly, evaporative concentration needs to beconducted in a manner which minimizes the generation of cookedoff-flavor, as well as insuring that the resulting orange juiceconcentrate has a relatively low viscosity.

The evaporative concentration processes of the present invention provideorange juice concentrates having a juice solids content of from about55° to about 75° Brix. Preferred evaporative concentrates of the presentinvention have juice solids content of from about 60° to about 70° Brix.These evaporative concentrates retain more of the desirable high-boilingflavor compounds, in particular valencene. They also tend to betterdisplay added orange aroma/flavor volatiles, in particular volatilespresent in the aqueous orange stripper essences and orange stripper oilsobtained from the stripped feed juice according to part B of thisapplication.

The evaporative orange juice concentrates of the present invention havea relatively low viscosity. In particular, the viscosity of theseconcentrates ranges from about 500 to about 6000 centipoise whenmeasured at a temperature of 8° C. Preferred concentrates of the presentinvention have viscosities of from about 2000 to about 4000 centipoise.By comparison, orange juice concentrates (58° to 72° Brix) prepared fromcurrent commercial feed juices by conventional TASTE evaporator systemstypically have viscosities of from about 8,000 to about 20,000centipoise. The viscosity of the concentrates of the present inventionis also relatively low when measured over a range of shears, i.e. theconcentrates of the present invention are less resistant to flow. Thislower resistance to flow means that the orange juice concentrates of thepresent invention melt faster and mix quicker with water than currentcommercial orange juice concentrates. (The method for measuring theviscosity of evaporative orange juice concentrates of the presentinvention is described hereafter in the evaporative concentrateanalytical methods section of part E of this application.)

The evaporative orange juice concentrates of the present invention haveeither no pectinesterase activity or else a relatively low level of suchactivity. In particular, evaporative concentrates of the presentinvention have a pectinesterase activity of about 0.5×10⁻⁴ P.E. units orless per °Brix, preferably about 0.1×10⁻⁴ P.E. units or less per °Brix.This pectinesterase activity is sufficiently low to prevent thedemethoxylation of pectins which could result in jellified lumps formingthat would increase the viscosity of the concentrate. (The method formeasuring the pectinesterase activity of evaporative orange juiceconcentrates of the present invention is described hereafter in theevaporative concentrate analytical methods section of part E of thisapplication.)

A particularly important characteristic of the orange juice concentratesof the present invention is their relatively low level of cookedoff-flavor. The term "cooked off-flavor" covers a variety of flavordescriptors. These descriptors include "cardboard-like", "caramelized","pineapple-overripe fruit-like", "apricot-like", "candy-like", and soforth. The presence of cooked off-flavor in the concentrate is anindicator of how much thermal abuse the juice has been subjected toduring evaporative concentration. In particular, TASTE concentrates,which are typically subjected to high temperatures for relatively longperiods of time, often have what is described as a high level of cookedoff-flavor.

For the purposes of the present invention, the relative level of cookedoff-flavor in the evaporative orange juice concentrate is measured bythe % retained valencene. As used herein, the term "% retainedvalencene" refers to the amount of valencene in the orange juiceconcentrate, relative to the amount of valencene in the feed juicebefore evaporative concentration (when the concentrate and feed juiceare normalized to a juice solids content of 11.8° Brix). Valencene canbe volatilized from the juice due to heat. Accordingly, it is believedthat a high % retained valencene is indicative of an orange juiceconcentrate which has been subjected to less thermal abuse duringevaporative concentration.

For evaporative concentrates of the present invention, the % retainedvalencene is at least about 28. Typically, % retained valencene is fromabout 28 to about 55. By contrast, conventional TASTE concentratesprepared from current commercial feed juices have a % retained valenceneof from about 11 to about 25. (The level of valencene is measured by thetissue homogenization analytical method described hereafter in part E ofthis application.)

The preferred evaporative concentration process of the present inventionstarts with a feed juice having: (1) a juice solids content of fromabout 9° to about 14° Brix, preferably from about 10° to about 12.5°Brix; (2) a viscosity of about 10 centipoise or less (i.e., from about 5to about 8 centipoise for non-Valencia feed juices, from about 7 toabout 10 centipoise for Valencia feed juices), and typically from about6 to about 9 centipoise, when measured at a temperature of 8° C.; (3) asinking pulp level of about 10% or less (i.e., from about 5 to about 8%for non-Valencia feed juices and from about 7 to about 10% for Valenciafeed juices), and typically from about 6 to about 9%; and (4)pectinesterase activity of from about 1×10⁻⁴ to about 5×10⁻⁴ P.E. unitsper °Brix (typically from about 1×10⁻⁴ to about 3×10⁻⁴ P.E. units per°Brix). The relatively low viscosity and sinking pulp level of the feedjuice is particularly important to the viscosity of the resulting orangejuice concentrate. It is also important to efficient evaporativeconcentration of the feed juice.

The preferred evaporative concentration process of the present inventioninvolves a plurality of evaporators. The evaporators used in thispreferred process are typically static surface evaporators. As usedherein, the term "static surface evaporator" refers to an evaporatorwhere the surface (or surfaces) in contact with the juice is essentiallystationary. There are at least two models of static surface evaporatorswhich are suitable for carrying out this preferred process. One is theSigmastar® plate evaporator made by W. Schmidt Gmbh & Co. K.G. ofBretten, West Germany. See U.S. Pat. No. 4,572,766 to Dimitriou, issuedFeb. 25, 1986 (herein incorporated by reference), which discloses thestructure of these Sigmastar® plate evaporators. The other is acassette-type evaporator made by Alfa-Laval AB of Tumba, Sweden. SeeU.S. Pat. No. 4,586,565 to Hallstrom et al, issued May 6, 1986 (hereinincorporated by reference), which discloses the structure of thesecassette-type evaporators. Sigmastar® plate evaporators are particularlypreferred static surface evaporators.

In this preferred evaporative concentration process, the feed juice isinitially preconcentrated so as to have a juice solids content of fromabout 15° to about 25° Brix. Preferably, the feed juice ispreconcentrated to a juice solids content of from about 15° to about18.5° Brix. This preconcentration of the feed juice is carried out byheating it in one or more evaporators at temperatures in the range offrom about 95° to about 160° F. The feed juice is heated for an averageof from about 5 to about 25 seconds per evaporator. Typically, the feedjuice is heated for an average of from about 15 to about 20 seconds perevaporator.

The number of evaporators used during this preconcentration of the feedjuice will depend on a number of factors, in particular the amount offeed juice which is being processed. Steam or vapors previouslygenerated from the feed juice can be used to supply the heat for theseevaporators. Where two or more evaporators are used in thispreconcentration step, the temperatures used generally increase as thejuice solids content of the feed juice increases. The particular numberof evaporators, the heating temperatures used in each evaporator, aswell as the heating time for each evaporator, should be selected so asto minimize the generation of cooked off-flavor.

A key aspect of this preferred evaporative concentration process is theintermediate concentration step used to further concentrate thispreconcentrated feed juice. This intermediate concentration step alsoserves the critical function of deactivating pectinesterase enzymespresent in the preconcentrated feed juice. Achievement of theseobjectives without generating a high level of cooked off-flavor requiresthe selection of a particular critical combination of processingconditions for this intermediate step. These critical conditionsinclude: (1) the juice solids content of the entering preconcentratedfeed juice; (2) the temperature to which the preconcentrated feed juiceis heated during this intermediate concentration step; (3) the timeperiod over which the preconcentrated feed juice is heated during thisintermediate concentration step; (4) the degree of shear across theheated surface of the evaporator to which the preconcentrated feed juiceis subjected during this intermediate concentration step; and (5) thejuice solids content of the resulting intermediately concentrated feedjuice.

This intermediate concentration step is carried out by heating thepreconcentrated feed juice (juice solids content of from about 15° toabout 25° Brix and pectinesterase activity of from about 1×10⁻⁴ to about5×10⁻⁴ P.E. units per °Brix.) under vacuum in one or more evaporators totemperatures ranging from about 160° to about 180° F. under conditionsof high shear across the heated surface of each evaporator. Thisintermediate step is usually carried out at pressures ranging from about4.5 to about 7.5 psia for an average of from about 5 to about 25 secondsper evaporator. Preferably, the preconcentrated feed juice is heated totemperatures ranging from about 165° to about 177° F. at pressuresranging from about 5.5 to about 7 psia for an average of from about 15to about 20 seconds per evaporator. The resulting intermediatelyconcentrated feed juice has a juice solids content of from about 25° toabout 40° Brix with a pectinesterase activity of about 0.5×10⁻⁴ P.E.units or less per °Brix. Preferred intermediately concentrated feedjuices have juice solids contents of from about 30° to about 37° Brix.

The deactivation of pectinesterase enzymes without excessive generationof cooked off-flavor still requires careful selection of the processingconditions during the intermediate concentration step within the broadranges defined above. For example, the higher the heating temperatureand the longer the average heating time used in this intermediateconcentration step, the lower should be the juice solids content of theresulting intermediately concentrated feed juice to avoid the generationof cooked off-flavor. Conversely, the lower the juice solids content ofthe resulting intermediately concentrated feed juice, the higher shouldbe the heating temperature and the longer should be the heating time toinsure effective deactivation of pectinesterase enzymes present in thejuice.

Conducting the intermediate concentration step under conditions of highshear across the heated surface of the evaporator(s) has also been foundto be important in deactivating pectinesterase enzymes present in thejuice. Static surface evaporators (e.g., Sigmastar® plate evaporators)used in carrying out this intermediate step generally operate by heatinga thin film of juice (e.g., a film having an average thickness of about0.004 in. or less) flowing at high velocity (e.g., about 100 ft. persec. or greater at the vapor-liquid interface) over the surface of theevaporator. Accordingly, as used herein, the term "high shear across theheated surface of each evaporator" refers to the type of shear generatedby such films flowing at such velocities across the evaporator surface.It is believed that the shears generated during the intermediateconcentration step are such that the components of the juice act as ifthey are being "stretched."

The intermediately concentrated juice is subsequently heated in one ormore evaporators at temperatures in the range of from about 170° toabout 100° F. for an average of from about 5 to about 25 seconds perevaporator to provide a highly concentrated juice having a juice solidscontent of from about 55° to about 75° Brix. This subsequentconcentration of the intermediately concentrated juice is basically forthe purpose of achieving a particular juice solids content in the finalorange juice concentrate. Generally, the heating temperatures andheating times are selected so as to efficiently achieve the finaldesired juice solids content without generating significant amounts ofcooked off-flavor. In particular, as the juice solids content of theintermediately concentrated feed juice increases, the heating times, andespecially heating temperatures, should conversely decrease to avoidgeneration of cooked off-flavor. As in the case of obtaining thepreconcentrated feed juice, the number of evaporators used dependsprimarily on the amount of juice being processed and the desired steameconomy, i.e., the amount of steam used. The highly concentrated juiceis then rapidly cooled to a temperature of about 65° F. or less(typically to from about 50° to about 55° F.) to provide the finalorange juice concentrate.

A specific seven-stage evaporative system involving Sigmastar® plateevaporators for carrying out the preferred evaporative concentrationprocess of the present invention is shown schematically in the Figureand is indicated by the number 10.

The seven evaporative stages used in system 10 are labeled E1 throughE7. The flow of feed juice FJ through this evaporative concentrationsystem is indicated by the solid arrows. This feed juice is heated ineach of evaporative stages E1 through E7 by steam supplied from sourcesS1 and S2, and vapors generated from the feed juice, as indicated by theopen arrows. Prior to entering the evaporative concentration system 10,feed juice FJ is sent to balance tank 12 and then pumped to preheater 14(typically a plate and frame heat exchanger) which typically heats thefeed juice to a temperature of about 113° F.

The preheated feed juice enters the evaporative concentration system 10at evaporative stage E6, which comprises two Sigmastar® plateevaporators connected in parallel. The feed juice is preconcentrated bypassing successively through evaporative stage E6, through aninterchanger indicated by 18 (typically a plate and frame heatexchanger) which typically heats the juice to a temperature of about146° F., and then through evaporative stages E4 and E3. Each of stagesE3 and E4 comprise two Sigmastar® plate evaporators connected inparallel. This preconcentrated feed juice then passes through aninterchanger indicated by 22 (typically a plate and frame heatexchanger), which typically heats the juice to about 170° F. before itreaches evaporative stage E1.

Evaporative stages E1 and E2 are where the crucial intermediateconcentration step occurs. Stages E1 and E2 each comprise one Sigmastar®plate evaporator. After the intermediately concentrated juice leavesevaporative stages E1 and E2, it is further concentrated by passagethrough evaporative stages E5 and E7. Stages E5 and E7 each comprise oneSigmastar® plate evaporator. As shown in the Figure, the highlyconcentrated juice having the desired juice solids content leavesevaporative stage E7, passes through a product cooler indicated by 26(typically a plate and frame heat exchanger) where it is typicallycooled rapidly to a temperature of about 60° F. or less. The cooledorange juice concentrate then exits the product cooler as indicated bythe letter P for further processing into orange juice products.

During heating of the juice in evaporative stages E1 through E7, vaporis generated which contains both water and orange aroma/flavorvolatiles. Some of this vapor condenses in each evaporative stage. Mostof the condensate from stage E1 is in the form of water which istypically discarded. The vapor from stages E2 through E7, and especiallyE3, E4 and E6, contains significant amounts of orange aroma/flavorvolatiles which can be collected and then processed in an aroma recoverysystem (not shown) to recover useful orange aroma/flavor materials. (Thevapors from E1, E2, E5 and E7 have lesser amounts of orange aroma/flavorvolatiles.)

In order to heat the juice in each of evaporative stages E1 through E6,steam indicated by S1 is supplied to thermocompressor 30. Thisthermocompressor also contains a portion (typically 50%) of the vaporgenerated by evaporative stage E1 which is recycled, as indicated by thebroken arrow, for increased steam efficiency. The steam/vapor streamfrom thermocompressor 30 heats the juice passing through evaporativestage E1. The remaining portion of the vapors generated from stage E1,as indicated by the open arrow, enter evaporative stage E2 where theyheat the juice passing through this stage. (In an optional embodiment,80% of these remaining vapors can go to stage E2 and 20% can go to stageE3.) As shown by the open arrows, vapors generated in stages E2, E3, E4and E5 are used to heat the juice passing through stages E3, E4, E5 andE6, respectively. (In an optional embodiment, 80% of the vapor generatedin stage E4 can go to stage E5, while the remaining 20% go to stage E6.)The vapor stream from evaporative stage E6 is cooled (typically in tubeand shell heat exchanger) to condense water, along with at least some ofthe orange aroma/flavor volatiles. This condensate from stage E6 is thencollected and processed in the aroma recovery system as previouslydiscussed.

As shown in the Figure, the juice passing through evaporative stage E7is heated by steam from a second source indicated by S2. During heatingof the juice in stage E7, the steam becomes sufficiently cool so as tocondense. This condensed steam from stage E7 can be collected and usedas a heating medium for preheater 14, or interchangers 18 or 22.

Some typical operating conditions (heating temperatures, pressures,juice solids content of exiting juice) for this seven stage evaporativesystem are shown in the following Table (starting feed juice of 11.6°Brix):

    ______________________________________                                                                       Solids Content                                 Evaporative                                                                              Temp.      Pressure Exiting Juice                                  Stage      (°F.)                                                                             (psia)   (°Brix)                                 ______________________________________                                        E1         172 ± 2 6.2      26.6                                           E2         160 ± 2 4.8      35.4                                           E3         150 ± 2 3.8      15.2                                           E4         141 ± 2 3.0      14.5                                           E5         125 ± 2 2.0      46.2                                           E6         111 ± 2 1.3      12.3                                           E7         116 ± 4 1.5      64.7                                           ______________________________________                                    

On a smaller scale, the preferred evaporative concentration process ofthe present invention can be carried out in a system involving fourevaporative stages. This smaller system uses evaporative stages E6 andE3 (one Sigmastar® evaporator for each stage) to preconcentrate thejuice (starting juice solids content of 12° Brix), evaporative stage E1(one Sigmastar® evaporator) to carry out the intermediate concentrationstep, and evaporative stage E5 (one Sigmastar® evaporator) to furtherconcentrate the intermediately concentrated juice to the desired juicesolids content for the final evaporative orange juice concentrate. Sometypical operating conditions (heating temperatures, pressures, juicesolids content of exiting feed juice) are shown in the following table:

    ______________________________________                                                                       Solids Content                                 Evaporative                                                                            Temp.        Pressure Exiting Juice                                  Stage    (°F.) (psia)   (°Brix)                                 ______________________________________                                        E1       174 ± 2   6.5      37.1                                           E3       159 ± 2   5.2      18.4                                           E5       135 ± 2   2.2      65.0                                           E6       110 to 122   1.2 to 1.8                                                                             14.4                                           ______________________________________                                    

Another, less preferred, evaporative concentration process for preparingorange juice concentrates of the present invention involves acentrifugal cone evaporator. This centrifugal cone evaporator has atleast one rotatable hollow cone-shaped member. While the rotatablemember is being rotated, the feed juice is sprayed onto its undersidesurface. The rotational speed is sufficiently great to centrifugallyspread the feed juice under conditions of high shear across theunderside surface. Due to gravity, the feed juice flows downwardly tothe bottom of the rotating member.

The underside surface of the rotating member is heated, usually by steamwhich is typically supplied through jackets formed in the rotatingmember. Typically, the steam is supplied at a saturated steamtemperature from about 185° to about 235° F. (preferably from about 212°to about 227° F.). This insures that the feed juice flowing across theheated underside surface of the rotating member is heated to a maximumtemperature of from about 100° to about 135° F., preferably from about110° to about 125° F. Since the feed juice is heated under a vacuum(typically from about 20 to about 30 in. of Hg), it is concentrated dueto evaporation. The resulting vapors which form pass out through the topof the rotating member. When the highly concentrated juice reaches thebottom of the rotating member, it has a juice solids content of fromabout 55° to about 75° Brix. This highly concentrated juice is typicallycentrifugally forced upwardly through an outlet to an expansion cooler(typically a shell and tube heat exchanger) where it is cooledimmediately to a temperature of about 90° F. or less (typically to fromabout 70° to about 85° F.) to provide the orange juice concentrate.

A suitable centrifugal cone evaporator for use in this process is theCentri-Therm evaporator made by Alfa-Laval AB, of Tumba, Sweden. In aCentri-Therm evaporator, the cone-shaped member is typically rotated ata speed of from about 1000 to about 1500 rpm. This rotational speedprovides an average feed juice film thickness on the underside surfaceof the cone-shaped member of about 0.002 inches or less with a velocityacross this underside surface of about 50 ft. per second or greater atthe vapor-liquid interface. Typically, the average residence time of thejuice on the underside surface of the rotating cone-shaped member of theCentri-Therm evaporator is about 1 second or less. See also U.S. Pat.No. 4,405,652 to Boucher, issued Sept. 20, 1983 (especially FIG. 4 andColumn 3, lines 5 to 45), which describes the structure and operation ofcentrifugal cone evaporators in reducing the alcohol content of wine.

While centrifugal cone evaporators provide orange juice concentrateshaving low viscosities with minimized levels of cooked off-flavor, theevaporative concentration process of the present invention involving aplurality of static surface evaporators is preferred for a number ofreasons. One is the ability to handle large volumes of feed juice, aswell as the cost of capital equipment. Another is efficient utilizationof steam (i.e. better steam economy) in the evaporative concentrationprocess. Most importantly, because the feed juice is heated in thecentrifugal cone evaporator to maximum temperatures too low todeactivate enzymes, the starting feed juice has to have lowpectinesterase activity, i.e. about 0.5×10⁻⁴ P.E. units or less per°Brix. This requires: (1) extremely gentle juice processing conditionsto produce low pectinesterase activity feed juices, usually at greatlydecreased juice yield; or (2) pasteurization of the feed juice beforeconcentration which can affect flavor quality and increase capitalequipment costs. These factors together make the preferred processinvolving a plurality of static surface evaporators more commerciallyattractive for obtaining large quantities of evaporative orange juiceconcentrate having relatively low viscosities with minimized levels ofcooked off-flavor.

The following are representative examples of orange juice concentratesobtained by the evaporative concentration processes of the presentinvention:

EXAMPLE 1

A Florida Early/Midseason feed juice which had been obtained under juiceprocessing conditions similar to those described in Example 2 of part Aof this application and which had been stripped of aroma/flavorvolatiles under conditions similar to those described in Example 1 ofpart B of this application was used. The characteristics of thisstripped feed juice were as follows:

    ______________________________________                                               Brix           11.6°                                                   Viscosity      6.0 cps                                                        Sinking pulp   8%                                                      ______________________________________                                    

The stripped feed juice was fed at the rate of 102 gallons per minute toa seven-stage evaporative system involving Sigmastar® plate evaporators.The operating conditions of this system were as follows:

    ______________________________________                                                                      Solids Content                                  Evaporative                                                                              Temp.      Pressure                                                                              Exiting Juice                                   Stage      (°F.)                                                                             (psia)  (° Brix)                                 ______________________________________                                        E1         172 ± 2 6.2     26.6                                            E2         160 ± 2 4.8     35.4                                            E3         150 ± 2 3.8     15.2                                            E4         141 ± 2 3.0     14.5                                            E5         125 ± 2 2.0     46.2                                            E6         111 ± 2 1.3     12.3                                            E7         116 ± 4 1.5     64.7                                            ______________________________________                                    

The highly concentrated juice from the E7 stage was rapidly cooled toabout 60° F. The resulting orange juice concentrate had the followingphysical and chemical characteristics:

    ______________________________________                                        Brix                64.7°                                              Brix/acid ratio     14.8                                                      Viscosity           3383 cps                                                  Sinking pulp        7%                                                        Glycosides          94.8 mg./100 ml.                                          P.E. units          0                                                         Valencene           615.9 ppb                                                 % Retained valencene                                                                              28.4                                                      ______________________________________                                    

EXAMPLE 2

A Florida Valencia feed juice which had been obtained under juiceprocessing conditions similar to those described in Example 4 of part Aof this application and which had been stripped of aroma/flavorvolatiles under conditions similar to those described in Example 2 ofpart B of this application was used. This stripped feed juice had asolids content of 12° Brix.

The stripped feed juice was fed at the rate of 17.8 gallons per minuteto a four-stage evaporator system involving Sigmastar® plateevaporators. The operating conditions of this system were as follows:

    ______________________________________                                                                       Solids Content                                 Evaporative                                                                              Temp.      Pressure Exiting Juice                                  Stage      (°F.)                                                                             (psia)   (°Brix)                                 ______________________________________                                        E1         174.5      6.7      37.1                                           E3         159.1      4.3      18.4                                           E5         135.2      2.4      65.0                                           E6         121.3      1.2 to 1.8                                                                             14.4                                           ______________________________________                                    

The highly concentrated juice from the E7 stage was rapidly cooled toabout 50° F. The resulting orange juice concentrate had the followingphysical and chemical characteristics:

    ______________________________________                                        Brix                 66.1°                                             Brix/acid ratio      14.5°                                             Viscosity            3075 cps                                                 Sinking pulp         8%                                                       Glycosides           120 mg/100 ml                                            P.E. Units           0.15 × 10.sup.-4                                   Valencene            6950 ppb                                                 % Retained valencene 43.6                                                     ______________________________________                                    

EXAMPLE 3

Late season Florida Valencia packinghouse oranges 2.5 to 3.5 inches insize were hand sorted to remove any undesirable fruit. The oranges wereextracted with a Brown Model 400 juice extractor operating at high peelclearance (3/16 inch) to minimize the oil content in the juice. The ragand seeds were removed from this extracted juice by using a Liquatexvibrating screen (10 mesh), followed by removal of the sensible pulpusing a Brown Model 3600 screw finisher (20 mesh). The feed juiceobtained had a solids content of 12.2° Brix.

The feed juice was concentrated using a Centri-Therm CT-1B centrifugalcone evaporator. The operating conditions of this evaporator were asfollows:

    ______________________________________                                        Feed rate           0.23 gal./min.                                            Steam temp.         104°-108° C.                                Rotational speed    1200 rpm                                                  Vacuum              27.0-27.5 in. Hg                                          Vapor temp.         40°-41° C.                                  ______________________________________                                    

The highly concentrated juice from the evaporator was cooled by thechiller to about 78° F. The resulting orange concentrate obtained hadthe following physical and chemical characteristics:

    ______________________________________                                        Brix                  63.9°                                            Brix/Acid ratio       17.9                                                    Sinking pulp (at 11.8° Brix)                                                                 6%                                                      Glycosides (at 11.8° Brix)                                                                   107 mg./100 ml.                                         ______________________________________                                    

D. Single-Strength orange juice products and orange juice concentrates

The orange juice products of the present invention can be in the form ofeither single-strength orange juice products, or else in the form oforange juice concentrates. The single-strength orange juice productshave a juice solids content of from about 8° to about 14° Brix.Preferably, such products have a juice solids content of from about 11°to about 13° Brix. For the orange juice concentrates, the juice solidscontent is from about 35° to about 65° Brix. Preferably, the juicesolids content is from about 40° (3 to 1 concentrate) to about 60° (5 to1 concentrate) Brix.

An important characteristic of these orange juice products is theirrelatively low viscosity. The single-strength products have a viscosityof about 7 centipoise or less at a temperature of 8° C. Thesesingle-strength products typically have a viscosity of from about 4 toabout 6 centipoise. The orange juice concentrates of the presentinvention, when reconstituted with water to a juice solids content ofabout 11.8° Brix, provide single-strength orange juice beverages havingviscosities like those of single-strength orange juice products of thepresent invention, i.e., about 7 centipoise or less at 8° C., with atypical viscosity range of from about 4 to about 6 centipoise. (Theviscosity of orange juice products of the present invention is measuredby the same methods used for the feed juice of part A of thisapplication.)

Another important characteristic of orange juice products of the presentinvention is their relatively low pectinesterase activity. Orange juiceproducts of the present invention have a pectinesterase activity ofabout 0.5×10⁻⁴ P.E. units or less per °Brix, and preferably about0.1×10⁻⁴ P.E. units or less per °Brix. This relatively lowpectinesterase activity prevents the demethoxylation of pectins whichcan jellify the juice product and thus increase its viscosity. (Thepectinesterase activity of orange juice products of the presentinvention is determined by the same method used for the evaporativeorange juice concentrates of part C of this application.)

Another important characteristic of orange juice products of the presentinvention is their level of titratable oil. The titratable oil contentof these products is about 0.015% or less (for concentrate products, thetitratable oil content is based on dilution to a juice solids content of11.8° Brix). The range of titratable oil contents is typically fromabout 0.004 to about 0.015%. Preferred orange juice products of thepresent invention have a titratable oil content of about 0.010% or less.The typical range of titratable oil contents for these preferredproducts is from about 0.004 to about 0.010%. (The titratable oilcontent of orange juice products of the present invention is measured bythe same method used to measure the titratable peel oil content of thefeed juice of part A of this application.)

Another important characteristic of orange juice products of the presentinvention is their orange aroma and flavor component. A key compound inthis orange aroma/flavor component is ethanol. The level of ethanol isusually an indicator of the concentration of "fresh" compounds in theorange juice product. The level of ethanol in orange juice products ofthe present can be from about 400,000 to about 1,200,000 parts perbillion (ppb). Preferred orange juice products have an ethanol level offrom about 500,000 to about 1,000,000 ppb.

The "fresh" aroma/flavor characteristics of orange juice products of thepresent invention are further defined by four other key volatilecompounds. These compounds are acetaldehyde, methanol, ethyl butyrate,and ethyl 3-hydroxyhexanoate. For acetaldehyde, this amount is fromabout 4000 to about 20,000 ppb, preferably from about 7000 to about14,000 ppb. For methanol, this amount is from about 10,000 to about60,000 ppb, preferably from about 25,000 to about 50,000 ppb. For ethylbutyrate, this amount is from about 500 to about 2000 ppb, preferablyfrom about 700 to about 1400 ppb. For ethyl 3-hydroxyhexanoate, thisamount is from about 100 to about 700 ppb, preferably from about 100 toabout 500 ppb. (The levels of ethanol, acetaldehyde, methanol and ethylbutyrate in orange juice products of the present invention are measuredby the purge and trap analytical method described hereafter in part E ofthis application. The level of ethyl 3-hydroxyhexanoate is measured bythe tissue homogenation analytical method described hereafter in part Eof this application.)

Another important compound defining the orange aroma/flavor component oforange juice products of the present invention is valencene. The levelof valencene is an important indicator of how "orangey" the orange juiceproduct is. For orange juice products of the present invention, theamount of valencene is from about 2000 to about 20,000 ppb. Preferably,this amount is from about 3000 to about 10,000 ppb. (The level ofvalencene in orange juice products of the present invention is measuredby the tissue homogenation analytical method described hereafter in partE of this application.)

The orange aroma/flavor component of orange juice products of thepresent invention is also characterized by a higher level of these moredesirable "fresh" and "orangey" compounds relative to the level of lessdesirable orange flavor compounds. The less desirable orange flavorcompounds include terpenes such as alpha-pinene and myrcene, andoxidation products such as hexanal, decanal, linalool, octanol,4-terpineol, alpha-terpineol, dodecanal and nootkatone. For orange juiceproducts of the present invention, the level of more desirable"fresh"/"orangey" compounds to less desirable orange compounds isdefined by the ratio of the combined amount of acetaldehyde, ethylbutyrate, ethyl 3-hydroxyhexanoate and valencene, to the combined amountof hexanal, alpha-pinene, myrcene, decanal, linalool, octanol,4-terpineol, alpha-terpineol, dodecanal and nootkatone. This ratio is atleast about 2:1, and typically ranges from about 2:1 to about 10.3:1,for orange juice products of the present invention. By comparison, thisratio is no more than 1.5 for current commercial orange juice productsprepared from orange juice concentrate and is at least 10.4 forhand-squeezed orange juice prepared from Florida Valencia oranges.

For orange juice products of the present invention, the level of each ofthe above less desirable orange flavor compounds are as follows:

    ______________________________________                                        Compound         Typical Level (ppb)                                          ______________________________________                                        hexanal          about 10 to about 300                                        alpha-pinene     about 100 to about 2000                                      myrcene          about 500 to about 3000                                      decanal          about 100 to about 1500                                      linalool         about 200 to about 2000                                      octanol          about 10 to about 300                                        4-terpineol      about 50 to about 300                                        alpha-terpineol  about 50 to about 300                                        dodecanal        about 30 to about 300                                        nootkatone       about 50 to about 1000                                       ______________________________________                                        Compound         Preferred Level (ppb)                                        ______________________________________                                        hexanal          about 30 to about 200                                        alpha-pinene     about 100 to about 1500                                      myrcene          about 800 to about 2800                                      decanal          about 50 to about 1000                                       linalool         about 200 to about 1000                                      octanol          about 10 to about 250                                        4-terpineol      about 50 to about 200                                        alpha-terpineol  about 50 to about 200                                        dodecanal        about 50 to about 200                                        nootkatone       about 100 to about 500                                       ______________________________________                                    

(The level of hexanal in orange juice products of the present inventionis measured by the purge and trap analytical method described hereafterin part E of this application. The levels of the remaining lessdesirable orange compounds are measured by the tissue homogenizationanalytical method described hereafter in part E of this application.)

The orange juice products of the present invention are formulated to anappropriate ratio of Brix solids to titratable acidity (TA). For orangejuice products of the present invention, this Brix solids to TA ratiocan be from about 12 to about 20. Preferred orange juice products of thepresent invention have a Brix solids to TA ratio of from about 14 toabout 17. This ratio can be adjusted by appropriate blending ofconcentrates having varying Brix solids to TA ratios.

The orange juice products of the present invention are also formulatedto have an appropriate level of sensible pulp. For single-strengthproducts, the level of sensible pulp can be from 0 to about 3%.Preferably, single-strength products have a sensible pulp level of fromabout 1 to about 2%. For orange juice concentrates, the level ofsensible pulp can be from about 2 to about 8%. Preferred orange juiceconcentrates have a sensible pulp level of from about 4 to about 6%.

The orange juice products of the present invention also have aparticularly low level of sinking pulp. As previously mentioned withregard to the feed juice in part A of this application, the level ofsinking pulp can have a significant effect on viscosity. Orange juiceproducts of the present invention typically have a sinking pulp level offrom about 4 to about 10%. Preferred orange juice products have asinking pulp level of from about 6 to about 9%. (The method formeasuring the sinking pulp level of orange juice products of the presentinvention is the same used for feed juices of part A of thisapplication.)

The orange juice products of the present invention are formulated byappropriate blending of orange juice concentrate, aroma and flavormaterials, sensible pulp, and water. The preferred source of orangejuice concentrate is that obtained by the evaporative concentrationprocess described in part C of this application. This preferred orangejuice concentrate can be blended with orange juice concentrates obtainedby other methods so long as these other concentrates are fairly bland inflavor and relatively low in viscosity. From about 30 to 100% of thispreferred orange juice concentrate is blended with from 0 to about 70%other concentrates. Preferably, from about 50 to 100% (most preferablyfrom about 90 to 100%) of this preferred orange juice concentrate isblended with from 0 to about 50% (most preferably from 0 to about 10%)other concentrates.

As previously mentioned, the orange juice concentrate used in preparingorange juice products of the present invention involves blendingconcentrates having varied ratios of Brix solids to TA. In addition, theorange juice concentrate used in formulating orange juice products ofthe present invention typically involves blending concentrates obtainedfrom different varieties of orange fruit. These orange juiceconcentrates are typically derived from Florida Early/Midseason andValencia orange fruit. Concentrates obtained from Florida Valenciaorange fruit are particularly preferred for orange juice products of thepresent invention. Concentrates obtained from other orange fruit, inparticular Brazilian Valencia fruit, can be formulated together withconcentrates obtained from Florida Early/Midseason and Valencia fruit.Typically, orange juice concentrates used in formulating orange juiceproducts of the present invention comprise the following blends ofconcentrates: from 0 to about 30% concentrate derived from FloridaEarly/Midseason fruit; from about 50 to 100% concentrate derived fromFlorida Valencia fruit; and from 0 to about 50% concentrate derived fromBrazilian Valencia fruit. Preferably, this blend of concentratescomprises from 0 to about 20% concentrate derived from FloridaEarly/Midseason fruit, from about 50 to 100% concentrate derived fromFlorida Valencia fruit, and from 0 to about 50% concentrate derived fromBrazilian Valencia fruit.

The orange juice concentrates used in formulating the orange juiceproducts of the present invention are fairly bland in terms of orangearoma/flavor. Accordingly, materials need to be added to thisconcentrate to impart the characteristic aroma and flavor of orangejuice. A preferred source of the aroma/flavor materials are the aqueousorange stripper essence and orange stripper oil obtained according topart B of this application. These stripper essences and stripper oilsare particularly preferred due to their high ratio of more desirableorange flavor compounds to less desirable orange flavor compounds.

The particular orange aroma and flavor characteristics of thesepreferred stripper essences and stripper oils can vary depending on thefeed juice from which they were obtained. Stripper essences and stripperoils which are obtained from feed juices derived from Florida Valenciaorange fruit have the most preferred orange aroma and flavorcharacteristics. The stripper essence comprises from 0 to about 50%(preferably from 0 to about 20%) Florida Early/Midseason and/orBrazilian Valencia essence and from about 50 to 100% (preferably fromabout 80 to 100%) Florida Valencia essence. Typical stripper oils usedcomprise similar amounts of Early/Midseason/Brazilian Valencia oils andFlorida Valencia oils.

While the stripper essences and stripper oils prepared according to partB of this application provide a significant portion of the desiredorange aroma/flavor impact, other sources of aroma/flavor materials areoften used in addition. For example, commercial orange essences such asFlorex 50041 (20:1 ethyl butyrate to hexanal ratio) and 56010, made byFlorex Flavors Ltd. of Eaton Park, Florida, and Natural Orange Aroma(#070570), Natural Orange Aroma Plus (#375002U), and Enriched Orange 3Fold Essence Oil (#375212U), made by Redd Citrus Specialities of SafetyHarbor, Florida, and commercial orange oils such as Florex 5801R,Citriff Orange #15980267, made by International Flavors and Fragrances,Inc. of New York City, New York, Valencene 85-90% purity (Citrus &Allied), made by Citrus & Allied Essences, Ltd. of Floral Park, N.Y.)and cold pressed peel oils, can be used to supply at least a portion ofthe aroma/flavor materials for orange juice products of the presentinvention. Non-orange sources of natural flavorings such as Orange withOther Natural Flavors #15980828, made by International Flavors andFragrances, Inc., and Natural Citrus Enhancer, Orange type made by Fries& Fries, Inc. of Cincinnati, Ohio, can also be used as a source ofaroma/flavor materials.

The source of sensible pulp for formulating orange juice products of thepresent invention is typically that removed from the partially finishedjuice as described in part A of this application. Commercial sources ofsensible pulp that are fairly bland in flavor and which have not beenexcessively abused or damaged can also be used in orange juice productsof the present invention.

A typical blending sequence in the preparation of orange juice productsof the present invention is as follows: an intermediate concentrate isprepared by adding a portion of the orange juice concentrate and theorange essence materials to a blend tank, followed by the orange oilmaterials and the remaining orange juice concentrate. Blending of thesematerials to form the intermediate concentrate is preferably done at amaximum temperature of about 30° F. Once all materials have been addedto the blend tank, they are typically mixed for at least 30 minutes toinsure that the orange oil materials are distributed homogeneouslythroughout the intermediate concentrate. This intermediate concentrateis preferably stored at a maximum temperature of about 20° F. prior touse.

Single-strength orange juice products and orange juice concentrates ofthe present invention are prepared by blending this intermediateconcentrate with the appropriate amount of sensible pulp, orangearoma/flavor materials and water. A typical blending sequence involvesadding water and sensible pulp to a blend tank, followed by thesimultaneous addition of the intermediate concentrate and orangearoma/flavor materials. Water or intermediate concentrate can be addedto this mixture for appropriate Brix solids adjustment. Also, orange oilmaterials can be added to achieve the appropriate titratable oilcontent.

Once prepared, the orange products of the present invention can befilled into cans, foil-like containers, cartons, bottles or otherappropriate packaging. The single-strength orange juice products aretypically pasteurized or sterilized prior to being filled into thepackaging. In the case of orange juice concentrate products, theseproducts are typically frozen after being filled into cans.

Representative examples of orange juice products made according to thepresent invention are as follows:

EXAMPLE 1

Late season Florida Valencia packinghouse oranges 2.5 to 3.5 inches insize were hand sorted to remove any undesirable fruit. The oranges wereextracted with a Brown Model 400 juice extractor operating at high peelclearance (3/16 inch) to minimize the oil content in the juice. The ragand seeds were removed from this extracted juice by using a Liquatexvibrating screen (10 mesh), followed by removal of the sensible pulpusing a Brown Model 3600 screw finisher (20 mesh). The feed juiceobtained had the following chemical and physical characteristics:

    ______________________________________                                        Brix                12.2°                                              Titratable acidity  0.73                                                      Peel oil            0.008%                                                    Glycosides          101 mg./100 ml.                                           ______________________________________                                    

The orange aroma and flavor volatiles from a portion of this feed juicewere stripped, condensed and collected using processing conditionssimilar to those described in Example 2 of part B of this application.The Valencia stripper essence obtained had the following composition:

    ______________________________________                                        Compound       Amount (ppm)                                                   ______________________________________                                        Ethanol        8826                                                           Acetaldehyde   134                                                            Ethyl acetate  8.08                                                           Ethyl butyrate 8.93                                                           Hexanal        0.43                                                           alpha-Terpineol                                                                              0.63                                                           ______________________________________                                    

The remaining unstripped feed juice was concentrated using aCentri-Therm CT-1B centrifugal cone evaporator. The operating conditionsof this evaporator were as follows:

    ______________________________________                                        Feed rate           0.23 gal./min.                                            Steam temp.         104°-108° C.                                Rotational speed    1200 rpm                                                  Vacuum              27.0-27.5 in. Hg                                          Vapor temp.         40°-41° C.                                  ______________________________________                                    

The highly concentrated juice from the evaporator was cooled by thechiller to about 78° F. The resulting orange concentrate obtained hadthe following physical and chemical characteristics:

    ______________________________________                                        Brix                  63.9°                                            Titratable acidity    3.57                                                    Sinking pulp (at 11.8° Brix)                                                                 6%                                                      Glycosides (at 11.8° Brix)                                                                   107 mg./100 ml.                                         ______________________________________                                    

The orange juice concentrate product was prepared from the followingingredients:

    ______________________________________                                        Ingredients       Amount (wt. %)                                              ______________________________________                                        Va1encia concentrate                                                                            63.8                                                        Valencia stripper essence                                                                       20.9                                                        Essence blend*    0.3                                                         Flavor booster**  0.17                                                        Sensible pulp     4.8                                                         Water             10.0                                                                          100.0                                                       ______________________________________                                         *Essence blend composition:                                                   Valencia TASTE essence  35%                                                   Early/Midseason TASTE essence  15%                                            Natural Orange Aroma Plus (#375002U)  25%                                     Natural Orange Aroma (#070570)  25%                                           **Flavor Booster composition:                                                 #D8118 Natural Citrus Enhancer, Orange Type  3.3%                             Orange with Other Natural F1avors (#15980828)  1.7%                           Ethanol  95.0%                                                           

In preparing this product, sensible pulp, Valencia stripper essence,essence blend, 10% of the Valencia concentrate and 90% of the water werecombined in a blend tank and mixed for about 5 minutes to form anintermediate concentrate. The remaining Valencia concentrate and waterwas then added to this intermediate concentrate and mixed for anadditional 10 minutes. During the last 5 minutes of this mixing, theflavor booster was added. The blend tank was insulated and chilled by aglycol system to keep the product between 32+ and 40° F. duringblending. The finished orange juice concentrate product was packed into12 oz. cans and then stored at -10° F. The physical and chemicalcharacteristics of this orange juice concentrate product were asfollows:

    ______________________________________                                        Brix                     42.4°                                         Titratable acidity       2.42                                                 Peel oil (at 11.8% Brix) 0.006%                                               Sinking pulp (at 11.8% Brix)                                                                           8%                                                   Flavor Composition (ppb)                                                      Acetaldehyde             13,591                                               Ethanol                  919,285                                              Methanol                 42,371                                               Ethyl butyrate           1299                                                 Ethyl 3-hydroxyhexanoate --                                                   Valencene                7310                                                 Hexanal                  34                                                   alpha-Pinene             280                                                  Myrcene                  944                                                  Decanal                  396                                                  Linalool                 385                                                  Octanol                  104                                                  4-Terpineol              --                                                   alpha-Terpineol          92                                                   Dodecanal                130                                                  Nootkatone               395                                                  ______________________________________                                    

EXAMPLE II

Late season Florida Valencia oranges were washed, sorted to remove anyundesirable fruit and deoiled using a Brown Oil Extractor. The deoiledoranges were extracted with Brown Model 400 and 700 juice extractorsoperating at high peel clearance (1/8 inch and 1/4 inch, respectively)to minimize the oil content in the juice. The rag and seeds were removedfrom this extracted juice by using a Liquatex vibrating screen (6 mesh),followed by removal of the sensible pulp using a Brown Model 3900 screwfinisher (20 mesh), and removal of additional sinking pulp using acentrifuge. Two feed juices were obtained, the second of which hadsignificantly more sinking pulp removed. The chemical and physicalcharacteristics of these two feed juices prior to centrifugation were asfollows:

    ______________________________________                                                    First      Second                                                 ______________________________________                                        Brix          11.3° 12.6°                                       Titratable acidity                                                                          0.61         0.74                                               Peel oil      0.011%       0.013%                                             Glycosides    124 mg./100 ml.                                                                            120 mg./100 ml.                                    Sinking pulp  14%          16%                                                ______________________________________                                    

The orange aroma and flavor volatiles from the first feed juice werestripped, condensed and collected using processing conditions similar tothose used in Example I. The Valencia stripper essence obtained had thefollowing composition:

    ______________________________________                                        Compound       Amount (ppm)                                                   ______________________________________                                        Ethanol        10975                                                          Acetaldehyde   82                                                             Ethyl acetate  1.6                                                            Ethyl butyrate 3.3                                                            Hexanal        1.0                                                            alpha-terpineol                                                                              2.8                                                            ______________________________________                                    

The first and second feed juices were concentrated using four SchmidtSigmastar plate evaporators under processing conditions similar to thosedescribed in Example 2 of part C of this application. The Valenciaconcentrates obtained had the following physical and chemicalcharacteristics:

    ______________________________________                                                         First                                                                              Second                                                  ______________________________________                                        Brix               61.2°                                                                         61.4°                                        Titratable acidity 3.4    3.8                                                 (at 11.8° Brix)                                                        Sinking pulp       8%     2%                                                  (at 11.8° Brix)                                                        ______________________________________                                    

The orange juice concentrate product was prepared from the followingingredients:

    ______________________________________                                        Ingredients       Amount (wt. %)                                              ______________________________________                                        Valencia concentrate*                                                                           67.3                                                        Valencia stripper essence                                                                       13.9                                                        Essence blend**   0.33                                                        Flavor Booster**  0.17                                                        Stripper oil      0.0085                                                      Cold pressed peel oil                                                                           0.0085                                                      Sensible pulp     4.8                                                         Water             13.5                                                                          100.0                                                       ______________________________________                                         *80% of first concentrate, 20% of second concentrate                          **Essence blend composition: Natural Orange Aroma Plus (#375002U)  75%        Natural Orange Aroma (#070570)  25%                                           ***Flavor Booster composition: #D8118 Natural Citrus Enhancer, Orange Typ      3.3% Orange with Other Natural Flavors (#15980828)  1.7% Ethanol  95.0% 

In preparing this product, sensible pulp, Valencia stripper essence,essence blend, 10% of the Valencia concentrate and 90% of the water werecombined in a blend tank and mixed for about 5 minutes. The stripper oiland cold pressed oil were added to this blend and then mixed for 5minutes to form an intermediate concentrate. The remaining Valenciaconcentrate and water was then added to this intermediate concentrateand mixed for an additional 10 minutes. During the last 5 minutes ofthis mixing, the flavor booster was added. The finished orange juiceconcentrate product was packed into 12 oz. cans and then stored at -10°F. The physical and chemical characteristics of this orange juiceconcentrate product were as follows:

    ______________________________________                                        Brix                 41.7°                                             Titratable acidity   0.69                                                     (at 11.8° Brix)                                                        Peel oil             0.006%                                                   (at 11.8° Brix)                                                        Sinking pulp         8%                                                       (at 11.8% Brix)                                                               Viscosity (at 11.8° Brix)                                                                   5.8 cps (average)                                        Flavor Composition (ppb)                                                      Acetaldehyde         7745                                                     Ethanol              888,442                                                  Methanol             27,436                                                   Ethyl butyrate       917                                                      Ethyl 3-hydroxyhexanoate                                                                           121                                                      Valencene            6341                                                     Hexanal              144                                                      alpha-Pinene         195                                                      Myrcene              846                                                      Decanal              311                                                      Linalool             752                                                      Octanol              21                                                       4-Terpineol          63                                                       alpha-Terpineol      163                                                      Dodecanal            52                                                       Nootkatone           237                                                      ______________________________________                                    

EXAMPLE III

Florida Valencia oranges were washed and sorted to remove anyundesirable fruit. Using juice processing conditions similar to thosedescribed in Example 4 of part A of this application, the oranges wereextracted with an FMC Low Oil juice extractor. The sensible pulp wasremoved from this extracted juice by using a FMC Model UCF 200 screwfinisher, followed by removal of additional sinking pulp using acentrifuge. The feed juice obtained had the following chemical andphysical characteristics:

    ______________________________________                                        Brix            12.3°                                                  Titratable acidity                                                                            0.91                                                          Peel oil        0.012%                                                        Glycosides      120 mg./100 ml.                                               Sinking pulp    10%                                                           Viscosity       9.0 cps                                                       ______________________________________                                    

The orange aroma and flavor volatiles in this feed juice were stripped,condensed and collected using processing conditions similar to thoseused in Example II. The Florida Valencia stripper essence obtained hadthe following composition:

    ______________________________________                                        Compound       Amount (ppm)                                                   ______________________________________                                        Ethanol        13177                                                          Acetaldehyde   119                                                            Ethyl acetate  4.3                                                            Ethyl butyrate 3.6                                                            Hexanal        0.9                                                            alpha-Terpineol                                                                              1.2                                                            ______________________________________                                    

The stripped feed juice was concentrated using four Schmidt Sigmastarplate evaporators under processing conditions similar to those describedin Example 2 of part C of this application. The Florida Valenciaconcentrate obtained had the following physical and chemicalcharacteristics:

    ______________________________________                                        Brix            63.2°                                                  Titratable acidity                                                                            4.39                                                          Sinking pulp    8%                                                            (at 11.8° Brix)                                                        Viscosity       5.6                                                           (at 11.8° Brix)                                                        Glycosides      116 mg./100 ml.                                               (at 11.8° Brix)                                                        ______________________________________                                    

Orange juice concentrate and single-strength products were prepared fromthe following ingredients:

    ______________________________________                                        Ingredients          Amount (wt. %)                                           ______________________________________                                        Florida Valencia Concentrate                                                                       32.6                                                     Brazilian TASTE Concentrate*                                                                       32.2                                                     Florida Valencia stripper essence                                                                  5.6                                                      Brazilian stripper essence**                                                                       2.9                                                      First Essence Blend***                                                                             0.4                                                      Florex Aroma #10     0.8                                                      Second Essence Blend****                                                                           0.16                                                     Stripper oil         0.019                                                    Cold pressed peel oil                                                                              0.008                                                    Enriched Orange 3 Fold                                                                             0.001                                                    Essence Oil (#375212U)                                                        Oil Blend*****       0.005                                                    Sensible pulp        4.8    [7.4]******                                       Water                20.5   [17.9]******                                                           100                                                      ______________________________________                                         *Brazillian TASTE concentrate physical and chemical characteristics: Brix     64.1° Titratable acidity  3.86 Peel oil  0.006% Sinking pulp  8%       Viscosity (at 11.8° Brix)  6.1 cps                                     **Obtained from Brazilian Valencia feed juice under similar processing        conditions as Florida Valencia stripper essence.                              ***Same as Essence Blend in Example II.                                       ****Second Essence Blend composition: Florida Valencia stripper essence       67% Florex #56010  33%                                                        *****Oil Blend composition: Florida Valencia stripper oil  8.3% Florida       Early/Mid stripper oil  3.0% Cold Pressed Valencia peel oil  20.4%            Enriched Orange 3 Fold Essence Oil (#375212U)  38.0% Citriff Orange           (#15980267)  23.2% C&A Valencene (85-90% purity)  7.1%                        ******No. in brackets concentrate blend for singlestrength product       

In preparing the concentrate product, sensible pulp, the stripperessences, the essence blends, 10% of the total concentrate and 90% ofthe water were combined in a blend tank and mixed for about 5 minutes.The stripper oil, cold pressed peel oil, essence oil and oil blend werethen added and mixed for five minutes to form an intermediateconcentrate. The remaining concentrate and water was then added to thisintermediate concentrate and mixed for an additional 10 minutes. Thefinished orange juice concentrate product was packed into 12 oz. cansand then stored at -10° F. The single-strength product was prepared thesame as the concentrate product, except that the finished concentratewas diluted with the appropriate amount of water and then sterilizedbefore being filled into cartons for storage at 34° F. The physical andchemical characteristics of these orange juice products were as follows:

    ______________________________________                                                      Concentrate                                                                             Single-Strength                                       ______________________________________                                        Brix            41.8°                                                                              11.6°                                      Titratable acidity                                                                            0.75        0.76                                              (at 11.8° Brix)                                                        Peel oil        0.013%      0.013%                                            (at ll.8° Brix)                                                        Sinking pulp    8%          8%                                                (at 11.8° Brix)                                                        Viscosity (at 11.8° Brix)                                                              5.4 cps     5.3 cps                                           Flavor Composition (ppb)                                                      Acetaldehyde          10,471                                                  Ethanol               706,053                                                 Methanol              44,775                                                  Ethyl butyrate        1012                                                    Ethyl 3-hydroxyhexanoate                                                                            243                                                     Valencene             3648                                                    Hexanal               127                                                     alpha-Pinene          1447                                                    Myrcene               2740                                                    Decanal               861                                                     Linalool              943                                                     Octanol               213                                                     4-Terpineol           196                                                     alpha-Terpineol       163                                                     Dodecanal             111                                                     Nootkatone            101                                                     ______________________________________                                    

E. Analytical Methods

1. Feed juice and orange juice products

a. Purge and trap headspace analysis

The purge and trap headspace analytical system consists of aHewlett-Packard (HP) 7675A purge and trap sampler and a HP 5880A gaschromatograph (G.C.). This analytical system is modified for automaticoperation. Sample introduction to a capillary column is achieved byadding a four port valve to the 7675A sampler and a cold trap to thecolumn oven of the 5880A G.C.

A 1 ml. sample of juice is placed into a sampling container (15 ml.volume culture tube) equipped with a Teflon®-coated stirring bar. Afterequilibration in a water bath (27°±1° C.) for 5 minutes with magneticstirring, the volatile compounds are swept into a room temperatureadsorption tube, by helium at a rate of 10 ml./min. for 1 minute. Theadsorption tube is filled with 200 mg. of Tenax® (80/100 mesh) adsorbent(Applied Science Division of Milton Roy Co.) and a small plug ofsilylated glass wool at each end to keep the adsorbent in place. Thishydrophobic polymer selectively adsorbs the organic volatiles and thehelium stream containing water is vented to atmosphere. The Tenax® tubeis then flushed one more minute with clean, dry helium gas (10 ml./min.,flow rate) to remove water from the trap. (This water can cause cloggingproblems by ice formation in the cold trapping system of the capillarycolumn.)

Sample injection into a capillary column is performed via desorption ofthe Tenax® trap and reconcentration of the desorbed sample onto thefirst portion (2 inches) of the capillary column. Thermal desorption iseffected by rapidly heating the Tenax® tube to 200° C. for 8 minuteswith helium flowing through it at a flow rate of 2.7 ml./min. The frontportion of the capillary column is located inside a trap cooled withliquid nitrogen (-150° C.). The sample is swept from the Tenax® tubeonto the capillary column where it condenses out in a narrow band atliquid nitrogen temperatures. For injection of the sample into thecapillary column, after cooling, this cold trap is heated very rapidly:it takes about 20 seconds to reach 140° C. and the temperature is heldat 140° C. for 1 minute. The helium switching valves and the cooling andheating sequences of the cold trap are controlled automatically in apre-programmed mode.

The capillary column used is a Durawax-3 fused silica capillary column(J&W Scientific, Inc., 0.32 mm. i.d×60 m. length). Durawax-3 is astabilized liquid phase which contains 50% of Carbowax-20M and 50% ofmethyl silicone. The carrier gas flow (He) at the capillary columnoutlet is 2.7 ml./min. (linear gas velocity=34.5 cm./sec. at 40° C.).The injection port and flame ionization detector temperatures are set at180° C. and 220° C., respectively. The column oven temperature is heldat 50° C. for 18 minutes, raised to 70° C. at 1.5° C./min., the raisedat 5° C./min. to 145° C. and then held at 145° C. for 8 minutes.

The compounds are identified by the retention times of peaks obtainedfor known standards and mass spectrometry. The purge and trap headspaceanalytical system was connected directly to a Finnigan Mat 4500 massspectrometer using a Super INCOS data system. Integration of peak areais obtained by use of a Hewlett-Packard 5880A series terminal, levelfour, or a Hewlett-Packard 3357E Laboratory Automation System. Thisautomated headspace analytical system provides good precision for mostof the aroma compounds (percent relative standard deviation=5.0-14.7%,n=6). Juice samples are analyzed at single strength, i.e., at 11.8°Brix.

In order to quantitate the concentration of the five identifiedcomponents (acetaldehyde, methanol, ethanol, ethyl butyrate and hexanal)in the orange juice, a linear regression analysis is performed usingstandard addition of individual components into orange juice stripped ofits volatile components. Five different concentration ranges withduplicated analytical data are used to construct the linear regressionequation shown in Table 1. Y represents peak area of the individualcomponents on the chromatogram. The concentration of the components inthe orange juice (ppm) is expressed as X (ppm can be converted to ppb bymultiplying it be 1000). From these equations, the concentration of thefive components in the orange juice is calculated from the peak area onthe headspace chromatogram obtained under the same analytical condition.

                  TABLE 1                                                         ______________________________________                                        Linear Regression Equation of Five Flavor Components                          and its Correlation Coefficient in Orange Juice                               Obtained Using Purge and Trap Headspace Analysis                                           Linear Regression                                                                            Correlation                                       Component    Equation       Coefficient                                       ______________________________________                                        Acetaldehyde Y = 158.94X + 1.88                                                                           0.998                                             Methanol     Y = 13.30 X + 51.20                                                                          0.998                                             Ethanol      Y = 24.53 X + 681.53                                                                         0.993                                             Ethyl butyrate                                                                             Y = 790.75 X - 1.20                                                                          0.998                                             Hexanal      Y = 326.58 X + 18.95                                                                         0.995                                             ______________________________________                                    

b. Tissue Homogenization Method

The tissue homogenization (TH) method is based on a direct extraction ofthe orange juice flavor components with a solvent, methylene chloride.After homogenization, the solvent layer is separated and evaporated to asmall volume. Quantitation is done using an internal standard.

A calibration standard is prepared as indicated below:

    ______________________________________                                        Compound          Amount (g)                                                                              mg./ml.                                           ______________________________________                                        Nootkatone        0.0694    0.6926                                            Valencene         0.4682    3.7456                                            Dodecanal         0.0410    0.3161                                            d-Carvone         0.0468    0.4610                                            Decanal           0.3382    3.1385                                            alpha-Terpineol   0.0920    0.9053                                            Ethyl-3-hydroxyhexanoate                                                                        0.0930    0.9179                                            Nonanal           0.0813    0.7967                                            Linalool          0.3432    3.3428                                            Octanol           0.0397    0.3950                                            gamma-Terpinene   0.0920    0.9044                                            Limonene          77.5689   773.3619                                          Octanal           0.4156    4.1061                                            Myrcene           1.2997    12.2302                                           alpha-Pinene      0.4243    4.1539                                            Ethyl butyrate    0.1791    1.7892                                            Hexana1           0.0399    0.3946                                            4-Terpineol       0.1015    0.9805                                            ______________________________________                                    

An internal standard solution is prepared by adding 10 microl. of propylbenzene to 40 ml of ethyl acetate. For calibration, 200 microl. of thecalibration standard mixture is spiked into orange juice concentratestripped of its volatile components. This calibration sample is dilutedto 11.8° Brix before use.

The analytical procedure is as follows: weigh 30 g of orange juice(11.8° Brix) into a 100 ml mass cylinder. The internal standard solution(50 microl.), methylene chloride (8 ml) and saturated salt solution (3ml) are added to the orange juice sample. The sample is then homogenizedfor 30 seconds. The homogenized sample is transferred to a centrifugetube and centrifuged at 10,000 rpms at 5° C. for 30 minutes. The bottomsolvent layer is transferred to a 5 ml vial and evaporated to a smallvolume under nitrogen.

A Hewlett-Packard 5880A gas chromatograph equipped with a capillarycolumn injector is used in the analysis. A Hewlett-Packard 3357minicomputer with basic program is used to obtain data from the gaschromatograph. The following conditions are used:

    ______________________________________                                        Air flow rate      300    ml./min.                                            Hydrogen flow rate 30     ml./min.                                            Nitrogen flow rate 30     ml./min.                                                                      (make up gas)                                       Helium flow rate   3      ml./min.                                                                      (carrier gas)                                                                 (20 psi setting)                                    Split flow         20     ml./min.                                            Septum purge flow  2-3    ml./min.                                            ______________________________________                                    

A DX-4 fused silica capillary column (0.32 mm.×60 m., J&W Scientific) isused for analysis.

The oven is heated at 50° C. for 5 minutes and then programmed to rise2° C./min. to a temperature of 120° C. The oven temperature then risesat 1.5° C./min. to a temperature of 160° C., then rises 8° C./min. to atemperature of 210° C., then rises at 3° C./min. to temperature of 240°C., and is then held at 240° C. for 10 minutes.

The methylene chloride extract of the calibration sample is injectedinto the gas chromatograph to establish the retention time and responsefactor for each component. The response factor of the calibrationextract is corrected for any residual levels present in the strippedorange juice concentrate, as previously determined. The identity of eachcompound in the chromatogram is confirmed using retention time data of aknown standard, as determined by a Finnigan MAT 4500 GC massspectrometer.

A Hewlett-Packard 3357 minicomputer is used to obtain data from the gaschromatograph. The amount of each compound in the juice sample (mg./ml.or ppb) is calculated as follows: ##EQU1##

c. Flavanoid glycoside analysis

A stock solution containing 240 mg. of hesperidin per 100 ml. isprepared by dissolving 300 mg. of 80% pure hesperidin in a 100 ml.volumetric flask containing 80 ml. of 0.1N NaOH, adjusting the pH to 7.0with glacial acetic acid, and then diluting to volume with distilledwater.

From this stock solution, standard solutions containing 40, 80, 120 and180 mg. of hesperidin per 100 ml. are also prepared.

The stock solution and the 4 standard solutions are used to obtain astandard spectrophotometric curve as follows:

For each solution, 3 test tubes are used (15 in all). Into each testtube is pipetted 5 ml. of diethyleneglycol (90% concentration) and 0.1ml. of the standard solution. After each test tube is mixed well with aVortex mixer, 0.1 ml. of 4N NaOH is added to the second and third testtubes, followed by mixing with a Vortex mixer. The test tubes areallowed to stand for 45 minutes for full development of yellow colorbefore spectrophotometric measurements are taken. The first test tubecontaining only standard solution and diethyleneglycol is used to zerothe spectrophotometer (Bausch & Lomb Spec. 21) at 420 nanom. for thesecond and third test tubes. The readings for the second and third testtubes are averaged to obtain the absorbency value for each standardsolution. The absorbency values for the stock and standard solutions areplotted to provide a standard curve from which absorbency values can beconverted into mg. of hesperidin per 100 ml.

Juice samples analyzed for flavanoid glycosides should be free ofsensible pulp, i.e. pulp which does not pass through a 20 mesh screen.The absorbency value for each juice sample is determined by the sameprocedure used to determine absorbency values for the stock and standardsolutions. The absorbency value for the juice sample is then comparedwith the standard curve to determine the mg. of hesperidin in the sampleper 100 ml.

d. Viscosity

Into the sample cup of a UL-adaptor is poured 16 ml. of a viscositystandard (known viscosity of 5 to 10 centipoise). A Brookfield LVTDrotational viscometer is set up with the UL-adaptor being placed in a25° C. waterbath. The viscosity standard in the sample cup is allowed toequilibrate in the waterbath for 10 minutes before a reading is taken at12 rpm. The known viscosity of the viscosity standard is divided by theaverage dial reading at 12 rpm to determine the response factor.

Sensible pulp is removed from the juice sample (solids content of 11.8°Brix) by passing it through a 20 mesh screen. (For concentrate products,water is added to dilute the juice sample to 11.8° Brix prior to pulpremoval.) Into the sample cup of the UL-adaptor is poured 16 ml. of thescreened sample. The UL-adaptor of the viscometer is placed in an 8° C.waterbath. The screened juice sample is allowed to equilibrate in thewaterbath for 15 minutes before a reading is taken at 12 rpm. Theviscosity of the juice sample at 12 rpm is determined by multiplying thedial reading by the response factor.

e. Volume % of sinking pulp

The juice is stirred enough to obtain a uniform sample. Sensible pulp isremoved from the sample by passing it through a 20 mesh screen. (Forconcentrate products, water is added to dilute the juice sample to 11.8°Brix prior to sensible pulp removal.) The screened sample isequilibrated to a temperature of 80±2° F. Two conical 50 ml. graduatedtubes are then filled with exactly 50 ml. each of the well mixed,equilibrated sample. The tubes are placed in the centrifuge (IEC ModelHN-SII, IEC Centrifuge Head #215, IEC Trunnion rings #325, IEC Shields#320) so that the graduated scale faces the direction of rotation. Withthe load balanced, the samples are centrifuged at 1500 rpm for 10minutes. The mls. of pulp at the bottom of each tube is read to thenearest ml. and then multiplied by 2 to get the volume % of sinkingpulp. The values for the tubes are averaged to obtain the volume % ofsinking pulp for sample.

f. Titratable peel oil content (Scott Oil Method)

This method is based on the Scott Oil Method described in Nagy et al,Citrus Science and Technology, Vol. 2 (1977), pp. 506-508. In thismethod, peel oil is distilled from an 2-propanol solution of the juicesample and then titrated with a standard KBr-KBrO₃ solution in an acidicmedium.

A 0.025N KBr-KBrO₃ titrant solution is prepared by diluting 1 part of a0.1N KBr-KBrO₃ solution (from RICCA Chemical Company, Arlington, Texas,Catalog No. 1170), with 3 parts distilled water. An acidic indicatorsolution is also prepared by mixing together 5 ml. of a 0.1% methylorange solution with 1000 ml. of a dilute hydrochloric acid solution (2parts distilled H₂ O, 1 part HCL).

A standard Scott Peel Oil Distillation Apparatus is used in this method.The apparatus essentially consists of a flat bottom distillation flask,and inclined adaptor and a distillation condenser.

A blank titration value (TB) is obtained by titrating 3 separatemixtures containing 25 ml. of 2-propanol and 10 ml. of the acidicindicator solution with the titrant solution and then dividing the totalml. of titrant solution used by 3.

For single-strength products and feed juices, 25 ml. of a well mixedjuice sample is pipetted into the distillation flask containing boilingchips or beads, followed by the addition of 25 ml. of 2-propanol. Themixture in the distillation flask is then heated to a temperature ofabout 85° C. Distillate is collected until condensation of water vaporappears on the transfer tube (approximately 35 ml. of distillate). Tothe distillate is then added 10 ml. of the acidic indicator solution.While being stirred with a magnetic stirrer, the acidic distillatesolution is titrated with titrant solution to a colorless endpoint. Thevolume of titrant solution required to reach the endpoint (TS) isrecorded. The % titratable peel oil for the sample is then obtained bythe following calculation:

    % titratable peel oil=(TS-TB)×0.004

For concentrate products, water is added until the sample is diluted to11.8° Brix. The titratable peel oil content of this diluted sample isthen determined by the same method used for single strength products andfeed juices.

2. Aqueous stripper essence

a. Capillary column gas chromatographic analysis of volatiles other thanethanol, methanol and acetaldehyde

A standard mixture solution is prepared by adding absolute ethanol (10ml.) to a 50 ml. volumetric flask, followed by various compounds presentin orange juice in the amounts indicated below:

    ______________________________________                                                           Amount    PPM                                              COMPOUND           microl.   (w/v)                                            ______________________________________                                        n-Propanol          40       3.21                                             Diacetyl            60       5.79                                             Ethyl acetate       150      13.49                                            Isobutanol          40       3.20                                             n-Butanol           25       2.01                                             1-Penten-3-ol       25       2.06                                             Ethyl propionate    40       3.56                                             Methyl butyrate     25       2.23                                             Acetal              150      12.42                                            Pentanol            40       3.25                                             Hexanal             40       3.22                                             Ethyl butyrate      150      13.16                                            trans-2-Hexenal     40       3.32                                             cis-3-Hexenol       40       3.34                                             Hexanol             40       3.23                                             Heptanal            40       3.00                                             Octanal             40       3.24                                             Limonene            40       3.35                                             Octanol             40       3.29                                             Linalool            80       6.78                                             Ethyl-3-hydroxyhexanoate                                                                          40       3.84                                             Terpinene-4-ol      30       2.67                                             alpha-Terpineol     40       3.70                                             Decanal             25       1.93                                             Neral               40       1.12                                             d-Carvone           20       1.89                                             Geraniol            30       2.51                                             Geranial            40       2.12                                             Thymol              41       4.10                                             Valencene           40       2.69                                             Nootkatone          30       2.52                                             ______________________________________                                    

After all of the above compounds are added to the flask, the standardmixture solution is diluted to volume with ethanol.

An internal standard solution is also prepared by adding a small volume(2-3 ml.) of distilled water to a 10 ml. volumetric flask. Cyclohexanone(25 microl.) is added and the water/ cyclohexanone internal standardsolution is diluted to volume with distilled water.

A calibration solution is prepared by pipetting 4 ml. of a 15% ethanolsolution into a 2 dram vial which is then spiked with 20 microl. of theinternal standard solution and 20 microl. of the standard mixturesolution.

A sample solution is prepared by first rinsing the pipette with aportion of the sample twice, pipetting 4 ml. of the sample into a 2 dramvial and then spiking the vial with 20 microl. of the internal standardsolution.

A Hewlett-Packard 5880A Gas Chromatograph equipped with a capillarycolumn injector is used in the analysis. A Hewlett-Packard 3357minicomputer with basic program is used to obtain data from the gaschromatograph. The following conditions are used:

    ______________________________________                                        Air flow rate      250    ml./min.                                            Hydrogen flow rate 30     ml./min.                                            Nitrogen flow rate 30     ml./min.                                                                      (make up gas)                                       Helium flow rate   2      ml./min.                                                                      (carrier gas)                                                                 (9.5 psi setting)                                   Split flow         10     ml./min.                                            Septum purge flow  3      ml./min.                                            ______________________________________                                    

A DB-1 fused silica capillary column (0.32 mm.×30 m., J&W Scientific) isused with the gas chromatograph.

The oven is heated at 40° C. for 7 minutes and then programmed to rise3.0° C./min. to a temperature of 80° C. The oven temperature then risesat 5° C./min. to a final temperature of 240° C., and is then held at240° C. for 5 minutes.

A 1 microl. portion of the calibration solution is injected into the gaschromatograph to establish the retention time and response factor forthe various compounds present. A 1 microl. portion of the samplesolution is injected into the gas chromatograph and then comparedagainst the calibration solution gas chromatograph to identify thevarious compounds. The amount of each compound in the sample solution(mg./ml. or ppm) is calculated as follows: ##EQU2##

b. Packed column gas chromatographic analysis of ethanol, methanol andacetaldehyde

An internal standard solution is prepared by adding n-propanol (0.2 ml.)to a 250 ml. volumetric flask, and then diluting to volume withdistilled water.

An acetaldehyde stock solution is also prepared by adding 5 ml. ofdistilled water to a 25 ml. volumetric flask. Acetaldehyde (1 ml.) isadded and the acetaldehyde stock solution is diluted to volume withdistilled water.

A calibration solution is prepared by adding 300 ml. of distilled waterto a 500 ml. volumetric flask, followed by 10 ml. of ethanol, 1 ml. ofmethanol and 8 ml. of the stock acetaldehyde solution. This calibrationsolution is diluted to volume with distilled water.

A calibration sample is prepared by pipetting 1 ml. of the calibrationsolution and 1 ml. of the internal standard solution into a 1 dram vial.

A sample solution is prepared by pipetting 1 ml. of the sample and 1 ml.of the internal standard solution into a 1 dram vial.

A Hewlett-Packard 5890 Gas Chromatograph equipped with a flameionization detector is used in the analysis. A Hewlett-Packard 3390Aintegrator is used to obtain data from the gas chromatograph. Thefollowing conditions are used:

    ______________________________________                                        Air flow rate         38 psi                                                  Hydrogen flow rate    12 psi                                                  Nitrogen flow rate    25 ml./min.                                             ______________________________________                                    

A Carbopack B/5% 80/120 mesh packed column (2 mm.×6 ft.) is used withthe gas chromatograph.

The oven is heated to 80° C. for 2 minutes and then programmed to rise8.0° C./min. to a temperature of 120° C. The injector temperature is150° C. While the detector temperature is 200° C.

A 1 microl. portion of the calibration sample is injected into the gaschromatograph to establish the retention time and response factor forethanol, methanol and acetaldehyde. A 1 microl. portion of the samplesolution is injected into the gas chromatograph and then comparedagainst the calibration sample gas chromatograph to identify the variouscompounds. The amount of each compound in the sample solution (mg./ml.or ppm) is calculated as follows: ##EQU3##

3. Capillary column gas chromatographic analysis of stripper oilvolatiles.

A standard mixture is prepared by adding the following compounds presentin orange oils in the amounts indicated below to a flask:

    ______________________________________                                                         Amount                                                       Compound         microl.   mg./ml.                                            ______________________________________                                        Acetaldehyde     50        0.4339                                             Methanol         70        0.6193                                             Ethanol          100       0.8841                                             Hexanal          30        0.2705                                             Ethyl butyrate   50        0.4915                                             trans-2-Hexanal  40        0.3721                                             cis-3-Hexenol    30        0.2803                                             Hexanol          30        0.2709                                             alpha-Pinene     400       3.7643                                             beta-Pinene      30        0.2876                                             Myrcene          1300      10.9795                                            Octanal          300       2.7260                                             Limonene         85000     798.3886                                           gamma-Terpinene  70        0.6246                                             Octanol          130       1.1982                                             Linalool         200       1.8983                                             Nonanal          70        0.6350                                             Citronellal      70        0.6245                                             Terpinene-4-oL   70        0.6968                                             alpha-Terpineol  70        0.7252                                             Decanal          400       3.4510                                             Neral (citral)   70        0.2195                                             d-Carvone        20        0.2120                                             Geraniol         20        0.1877                                             Geranial (citral)                                                                              70        0.4146                                             Perillaldehyde   40        0.3536                                             Dodecanal        48.6      0.3505                                             Caryophellene    30        0.2726                                             Valencene        400       3.0147                                             Nootkatone       70        0.6582                                             ______________________________________                                    

An internal standard solution is also prepared by adding a small volume(10-20 ml.) of ethyl acetate to a 100 ml. volumetric flask. Propylbenzene (300 microl.) is added and then the internal standard solutionis diluted to volume with ethyl acetate.

A calibration solution is prepared by adding 1 ml. of the standardmixture solution and 1 ml. of the internal standard solution to a 1 dramvial.

A sample solution is prepared by first rinsing the pipette with aportion of the sample twice, and then pipetting 1 ml. of the sample and1 ml. of the internal standard solution into a 1 dram vial.

A Hewlett-Package 5880A Gas Chromatograph equipped with a capillarycolumn injector is used in the analysis. A Hewlett-Packard 3357minicomputer with basic program is used to obtain data from the gaschromatograph. The following conditions are used:

    ______________________________________                                        Air flow rate   250    ml./min.                                               Hydrogen flow rate                                                                            30     ml./min.                                               Nitrogen flow rate                                                                            30     ml./min. (make up gas)                                 Helium flow rate                                                                              3      ml./min. (carrier gas)                                                        (20 psi setting)                                       Split flow      105    ml./min.                                               Septum purge flow                                                                             3      ml./min.                                               ______________________________________                                    

A DX-4 fused silica capillary column (0.32 mm.×60 m., J&W Scientific) isused with the gas chromatograph.

The oven is heated at 55° C. for 5 minutes and then programmed to rise2° C./min. to a temperature of 120° C. The oven temperature then risesat 1.5° C./min. to a temperature of 160° C., than at 4° C./min. to afinal temperature of 220° C., and is then held at 220° C. for 10minutes.

A 1 microl. portion of the calibration solution is injected into the gaschromatograph to establish the retention time and response factor forthe various compounds present. A 1 microl. portion of the samplesolution is injected into the gas chromatograph (using solvent plugtechnique) and then compared against the calibration solution gaschromatograph to identify the various compounds. The amount of eachcompound in the sample solution is calculated as follows: ##EQU4##

4. Evaporative orange juice concentrate

a. Viscosity

The viscosity of juice concentrates is determined by the same method asE(1)(d) for feed juices, but using a RVT Brookfield viscometer with aNo. 6 or 7 spindle rotated at 100 rpm.

b. Pectinesterase Activity

This method determines the amount of activity of the enzyme pectinmethylesterase (pectinesterase) in the juice or juice concentrate.

A 2M sodium chloride stock solution is prepared by placing 58.45 gramsof sodium chloride in a 500 ml. volumetric flask, adding distiled waterto the mark and then shaking until the sodium chloride is completelydissolved.

A 1% pectin/salt solution is prepared as follows: a 75 ml. portion ofthe 2M sodium chloride stock solution is placed in a 1 liter volumetricflask which is then diluted to the mark with distilled water. Theblender jar (Waring blender) is then filled approximately 3/4 full withthis solution. Using a variable transformer, the blender is run at anapproximately 40% setting. Pure citrus pectin (10±0.1 g.) is slowlysifted into the blender jar, followed by the remaining 1/4 of the saltsolution. This 1% pectin/salt solution is then blended for approximately1 minute.

Pectinesterase activity in the sample is determined as follows: a 100ml. portion of the 1% pectin/salt solution is placed in a 250 ml. beakerwhich is brought to a temperature of 35° C.±1° C. by using a water bath.A 10 ml. juice concentrate sample diluted to 11.8° Brix is then pipettedinto the solution in the beaker. A magnetic stirrer is placed in thesolution, followed by insertion of pH meter electrodes (FisherTitrimeter II Fep) and then the solution is stirred slowly. Enough 0.10NNaOH solution is added to raise the pH of the solution to just barelyover 7.5, e.g. 7.6. When the pH of the solution lowers to exactly 7.5,0.02N NaOH is added for 10 minutes at a rate that will hold the pH asnear 7.5 as possible. The milliliters of 0.02N NaOH required during this10 minute period are used in the following calculation to determinepectinesterase activity (P.E. Units) of the juice concentrate sample per°Brix:

    P.E. Units per °Brix=[(milliliters of 0.02N NaOH×0.02]/[(°Brix of Sample)×100]

What is claimed is:
 1. A method for obtaining a commercial feed juicefrom orange fruit, which comprises the steps of:a. selecting processableorange fruit; b. processing the selected fruit by:(1) gently extractingjuice from the selected fruit in a commercial juice extractor to provideextracted juice having about 0.015% or less titratable peel oil; (2)gently and quickly removing non-juice materials from the extracted juiceto provide a partially finished juice; (3) removing sensible pulp fromthe partially finished juice to provide a completely finished juicesubstantially free of sensible pulp and having:(a) a viscosity of atleast about 10 centipoise at a temperature of 8° C.; and (b) at leastabout 10% sinking pulp; and (4) removing at least some of the sinkingpulp from the completely finished juice to provide a commercial feedjuice suitable for use in aroma/flavor volatile stripping andevaporative concentration processing, the feed juice having:(a) aviscosity of from about 7 to about 10 centipoise at a temperature of 8°C.; (b) from about 5 to about 10% sinking pulp; (c) about 0.015% or lesstitratable peel oil; (d) about 175 mg. or less, per 100 ml., offlavanoid glycosideswherein the ratio of the combined amount ofacetaldehyde, methanol, ethyl butyrate, ethyl 3-hydroxyhexanoate andvalencene, to the combined amount of hexanal, alpha-pinene, myrcene,decanal, linalool and octanal in the feed juice is from about 8.5 toabout 21.5.
 2. The method of claim 1 wherein the titratable peel oillevel of the extracted juice and the feed juice is from about 0.004 toabout 0.015%.
 3. The method of claim 2 wherein the commercial juiceextractor is a reciprocating cup-type and wherein the juice yield is atleast about 90%.
 4. The method of claim 3 wherein the juice yield isfrom about 92 to about 95%.
 5. The method of claim 2 wherein thecompletely finished juice has a viscosity of from about 12 to about 34centipoise and from about 12 to about 30% sinking pulp.
 6. The method ofclaim 5 wherein the feed juice has from about 100 to about 200 mg., per100 ml., of flavanoid glycosides.
 7. The method of claim 6 wherein theorange fruit is Valencia orange fruit.
 8. The method of claim 1 whereinthe level of titratable peel oil of the extracted juice and the feedjuice is about 0.010% or less.
 9. The method of claim 1 which comprisesthe further step of deoiling the selected fruit prior to step b(1).